Merge pull request 'release: offline mode + local pass-and-play (hotseat) — proposed v1.12.0' (#212) from development into master

The 2-4 hotseat players now start in a random seating order (so who goes
first, and the turn order, is random) — matching the online games. The
engine starts at seat 0, so shuffling the seats at creation picks the
starter; the shuffle is seed-driven (a distinct derivation from the tile
bag), so replay reproduces it. Scoped to hotseat — vs_ai stays human-first.
- lib/roster.ts: shuffleSeeded (unit-tested); NewGame shuffles buildSeats
  with the game seed before create.
- e2e: pin a seed that keeps the roster order so the lock assertions stay
  deterministic.

.gitea/workflows/ci.yaml

@@ -214,9 +214,21 @@ jobs:
         run: pnpm exec playwright install chromium webkit
         timeout-minutes: 5
 
+      # The offline e2e plays a real local vs_ai game, so it needs the per-variant dawgs; fetch the
+      # release the same way the Go jobs do and point the mock preview's copy step (scripts/
+      # e2e-dict.mjs, via E2E_DICT_DIR below) at it.
+      - name: Fetch dictionary DAWGs
+        run: |
+          mkdir -p "${GITHUB_WORKSPACE}/dawg"
+          curl -fsSL -o /tmp/dawg.tar.gz "https://gitea.iliadenisov.ru/developer/scrabble-dictionary/releases/download/${DICT_VERSION}/scrabble-dawg-${DICT_VERSION}.tar.gz"
+          tar xzf /tmp/dawg.tar.gz -C "${GITHUB_WORKSPACE}/dawg"
+          ls -la "${GITHUB_WORKSPACE}/dawg"
+
       - name: E2E smoke (mock)
         run: pnpm run test:e2e
         timeout-minutes: 5
+        env:
+          E2E_DICT_DIR: ${{ github.workspace }}/dawg
 
   # conformance proves the client's local move preview (the ported dawg reader +
   # validator, ui/src/lib/dict) byte-for-byte against the authoritative Go engine:
@@ -252,6 +264,7 @@ jobs:
         run: |
           go run ./backend/cmd/dictgen -dawg-dir "${GITHUB_WORKSPACE}/dawg" -out /tmp/dictgold
           go run ./backend/cmd/validategen -dawg-dir "${GITHUB_WORKSPACE}/dawg" -out /tmp/validgold
+          go run ./backend/cmd/movegen -dawg-dir "${GITHUB_WORKSPACE}/dawg" -out "${GITHUB_WORKSPACE}/movegold"
 
       - name: Set up Node
         uses: actions/setup-node@v4
@@ -271,6 +284,7 @@ jobs:
           DICT_DAWG_DIR: ${{ github.workspace }}/dawg
           DICT_GOLD_DIR: /tmp/dictgold
           DICT_VALID_DIR: /tmp/validgold
+          DICT_MOVEGEN_DIR: ${{ github.workspace }}/movegold
         run: pnpm exec vitest run src/lib/dict/
 
   # gate is the single branch-protection required check. It always runs and passes

backend/cmd/backend/main.go

@@ -12,7 +12,6 @@ import (
 	"fmt"
 	"log"
 	"os/signal"
-	"strings"
 	"syscall"
 	"time"
 
@@ -216,11 +215,9 @@ func run(ctx context.Context, cfg config.Config, logger *zap.Logger) error {
 	// Operator alert emails on new feedback / word complaints, coalesced into one digest
 	// per interval. Inert unless a distinct admin sender and recipient are configured.
 	if cfg.SMTP.AdminFrom != "" && cfg.SMTP.AdminTo != "" {
-		consoleURL := ""
+		// The alert digest carries no admin-console link on purpose — an admin URL must not
-		if cfg.PublicBaseURL != "" {
+		// travel in an email (a mail provider could cache or index it); see adminalert.New.
-			consoleURL = strings.TrimRight(cfg.PublicBaseURL, "/") + "/_gm"
+		alerts := adminalert.New(mailer, feedbackSvc, games, cfg.SMTP.AdminFrom, cfg.SMTP.AdminTo, logger)
-		}
-		alerts := adminalert.New(mailer, feedbackSvc, games, cfg.SMTP.AdminFrom, cfg.SMTP.AdminTo, consoleURL, logger)
 		go alerts.Run(ctx, adminAlertInterval)
 		logger.Info("admin alert worker started", zap.Duration("interval", adminAlertInterval))
 	}

backend/cmd/movegen/main.go

@@ -0,0 +1,417 @@
+// Command movegen emits golden conformance fixtures for the client-side move
+// generator port (ui/src/lib/dict). It is a dev tool, run by hand; its output is
+// committed so the TypeScript parity tests run without a Go toolchain.
+//
+// For each small sample dictionary (English and Russian — the latter reaches
+// alphabet index 32, exercising the 33-letter cross-set boundary) it writes:
+//
+//   - sample_<tag>.dawg           the serialized dictionary (the reader/cursor fixture)
+//   - sample_<tag>.words.json     the stored words + their alphabet indexes
+//   - sample_<tag>.gen.json       ranked move-generation results from the real solver,
+//     for a handful of positions, plus the ruleset the TS
+//     side rebuilds to score identically
+//
+// Positions are built with only the solver's public API: an empty board, and
+// two-ply positions reached by applying the solver's own top move (so no internal
+// encoding is needed). Regenerate with:
+//
+//	go run ./backend/cmd/movegen -out ui/src/lib/dict/testdata
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"flag"
+	"log"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"gitea.iliadenisov.ru/developer/scrabble-solver/board"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/rack"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/rules"
+	"gitea.iliadenisov.ru/developer/scrabble-solver/scrabble"
+	dawg "github.com/iliadenisov/dafsa"
+)
+
+// sampleWordsEN is the English sample dictionary, in strictly increasing
+// alphabet-index order (the builder requires it). Shared prefixes (car/care/cars),
+// shared suffixes (cats/dogs), internal-final nodes (do, an) and a one-letter word.
+var sampleWordsEN = []string{
+	"a", "an", "and", "ant",
+	"car", "care", "cared", "cares", "cars", "cat", "cats",
+	"do", "doe", "does", "dog", "dogs", "done", "dot",
+}
+
+// sampleWordsRU is the Russian sample dictionary, in strictly increasing index
+// order. It deliberately includes words starting with я (index 32) so the ported
+// cross-set handles alphabet indexes past JS's 31-bit shift boundary.
+var sampleWordsRU = []string{"ад", "ар", "оса", "я", "яд", "яр"}
+
+// sampleFixture is the JSON committed with the .dawg so the TypeScript cursor test
+// knows the exact word set (as alphabet indexes) to expect from enumeration.
+type sampleFixture struct {
+	Alphabet string   `json:"alphabet"`
+	NumAdded int      `json:"numAdded"`
+	Words    []string `json:"words"`
+	Indexes  [][]int  `json:"indexes"`
+}
+
+// genFixture is the move-generation golden set for one sample dictionary.
+type genFixture struct {
+	Ruleset genRuleset `json:"ruleset"`
+	Cases   []genCase  `json:"cases"`
+}
+
+// genRuleset is the scoring data the TS side rebuilds so evaluate() matches the Go
+// solver: letter values, premium multipliers per square, the centre, rack size and bonus.
+type genRuleset struct {
+	Size       int     `json:"size"`
+	Cols       int     `json:"cols"`
+	Center     int     `json:"center"`
+	RackSize   int     `json:"rackSize"`
+	Bingo      int     `json:"bingo"`
+	Values     []int   `json:"values"`
+	LetterMult [][]int `json:"letterMult"`
+	WordMult   [][]int `json:"wordMult"`
+}
+
+// genTile is one placed tile (a board tile or a move placement).
+type genTile struct {
+	Row    int  `json:"row"`
+	Col    int  `json:"col"`
+	Letter int  `json:"letter"`
+	Blank  bool `json:"blank"`
+}
+
+// genRack is a rack as a multiset of letter indexes plus a blank count.
+type genRack struct {
+	Letters []int `json:"letters"`
+	Blanks  int   `json:"blanks"`
+}
+
+// genMove is one ranked generated play: its orientation, placed tiles and total score.
+type genMove struct {
+	Dir   int       `json:"dir"`
+	Tiles []genTile `json:"tiles"`
+	Score int       `json:"score"`
+}
+
+// genCase is one generation position: the tiles already on the board (empty when
+// none), the rack, the mode/rule and the ranked moves the solver returns.
+type genCase struct {
+	Name             string    `json:"name"`
+	Placed           []genTile `json:"placed"`
+	Rack             genRack   `json:"rack"`
+	Mode             int       `json:"mode"`
+	IgnoreCrossWords bool      `json:"ignoreCrossWords"`
+	Moves            []genMove `json:"moves"`
+}
+
+func main() {
+	out := flag.String("out", "ui/src/lib/dict/testdata", "output directory for fixtures")
+	dawgDir := flag.String("dawg-dir", "", "when set, emit real-dictionary move-gen golden from the .dawg files in this dir (conformance mode) instead of the committed samples")
+	flag.Parse()
+
+	if err := os.MkdirAll(*out, 0o755); err != nil {
+		log.Fatalf("movegen: mkdir %s: %v", *out, err)
+	}
+
+	if *dawgDir != "" {
+		buildReal(*dawgDir, *out)
+		return
+	}
+
+	emitRulesets()
+
+	buildSample(*out, "en", rules.English(), sampleWordsEN, []genCase{
+		emptyCase("empty-cared", englishRack("caredts", 0), scrabble.Both, false),
+		emptyCase("empty-dogs", englishRack("dogsent", 0), scrabble.Both, false),
+		emptyCase("empty-blank", englishRack("caret", 1), scrabble.Both, false),
+		emptyCase("empty-single-word", englishRack("caredts", 0), scrabble.Both, true),
+	})
+
+	buildSample(*out, "ru", rules.RussianScrabble(), sampleWordsRU, []genCase{
+		emptyCase("empty-yad", russianRack("ядрасо", 0), scrabble.Both, false),
+	})
+}
+
+// buildSample writes the dawg, the word fixture and the generation golden set for
+// one sample dictionary. Two-ply cases are appended: the solver's own top move from
+// the first non-empty result is applied, then generation runs again on the new rack.
+func buildSample(out, tag string, rs *rules.Ruleset, words []string, cases []genCase) {
+	idx := rs.Alphabet
+	b := dawg.New(idx)
+	indexes := make([][]int, 0, len(words))
+	for _, w := range words {
+		if err := b.Add(w); err != nil {
+			log.Fatalf("movegen[%s]: add %q: %v", tag, w, err)
+		}
+		enc, err := idx.Encode(w)
+		if err != nil {
+			log.Fatalf("movegen[%s]: encode %q: %v", tag, w, err)
+		}
+		ints := make([]int, len(enc))
+		for i, x := range enc {
+			ints[i] = int(x)
+		}
+		indexes = append(indexes, ints)
+	}
+	finder := b.Finish()
+
+	writeJSON(filepath.Join(out, "sample_"+tag+".words.json"), sampleFixture{
+		Alphabet: tag, NumAdded: finder.NumAdded(), Words: words, Indexes: indexes,
+	})
+	dawgPath := filepath.Join(out, "sample_"+tag+".dawg")
+	if _, err := finder.Save(dawgPath); err != nil {
+		log.Fatalf("movegen[%s]: save %s: %v", tag, dawgPath, err)
+	}
+
+	s := scrabble.NewSolver(rs, finder)
+	for i := range cases {
+		runCase(s, rs, &cases[i], nil)
+	}
+	// A two-ply position from the first standard case that produced a move.
+	if two := twoPly(s, rs, cases); two != nil {
+		cases = append(cases, *two)
+	}
+
+	writeJSON(filepath.Join(out, "sample_"+tag+".gen.json"), genFixture{
+		Ruleset: rulesetOf(rs), Cases: cases,
+	})
+	log.Printf("movegen[%s]: %d words, %d cases", tag, finder.NumAdded(), len(cases))
+}
+
+// realVariant maps a shipped dictionary file to the ruleset that scores it and the racks
+// the conformance positions use. smallRack/blankRack keep the first-move (empty board)
+// lists bounded on a dense dictionary; fullRack drives a deep 7-tile mid-game position,
+// kept small by the anchors around the already-placed word.
+type realVariant struct {
+	file, variant, smallRack, blankRack, fullRack string
+	rs                                            *rules.Ruleset
+}
+
+// buildReal emits move-generation golden from the real shipped dictionaries in dawgDir —
+// the full alphabets and deep graphs the tiny samples cannot reach — one
+// <variant>.movegen.json per variant. Like the dictgen/validategen vectors it is
+// regenerated in CI and never committed, so it pins no dictionary version into the repo.
+func buildReal(dawgDir, out string) {
+	reals := []realVariant{
+		{"en_sowpods", "scrabble_en", "aine", "ain", "aeinrst", rules.English()},
+		{"ru_scrabble", "scrabble_ru", "аеин", "аен", "аеиноср", rules.RussianScrabble()},
+		{"ru_erudit", "erudit_ru", "аеин", "аен", "аеиноср", rules.Erudit()},
+	}
+	for _, v := range reals {
+		data, err := os.ReadFile(filepath.Join(dawgDir, v.file+".dawg"))
+		if err != nil {
+			log.Fatalf("movegen[%s]: read dawg: %v", v.variant, err)
+		}
+		finder, err := dawg.Read(bytes.NewReader(data), 0)
+		if err != nil {
+			log.Fatalf("movegen[%s]: parse dawg: %v", v.variant, err)
+		}
+		s := scrabble.NewSolver(v.rs, finder)
+
+		cases := []genCase{
+			emptyCase("first-move", encRack(v.rs, v.smallRack, 0), scrabble.Both, false),
+			emptyCase("first-move-blank", encRack(v.rs, v.blankRack, 1), scrabble.Both, false),
+		}
+		for i := range cases {
+			runCase(s, v.rs, &cases[i], nil)
+		}
+		// A deep 7-tile mid-game: place the top first move, then generate again. The
+		// anchors around the placed word bound the list while still exercising a full rack,
+		// deep left/right extension and wide cross-sets over the real graph.
+		full := encRack(v.rs, v.fullRack, 0)
+		b := board.New(v.rs.Rows, v.rs.Cols)
+		if m1 := s.GenerateMovesOpts(b, toRack(v.rs.Size(), full), scrabble.Both, scrabble.PlayOptions{}); len(m1) > 0 {
+			mid := genCase{Name: "mid-game", Rack: full, Mode: int(scrabble.Both)}
+			runCase(s, v.rs, &mid, tilesOf(m1[0].Tiles))
+			cases = append(cases, mid)
+		}
+
+		writeJSON(filepath.Join(out, v.variant+".movegen.json"), genFixture{Ruleset: rulesetOf(v.rs), Cases: cases})
+		total := 0
+		for _, c := range cases {
+			total += len(c.Moves)
+		}
+		_ = finder.Close()
+		log.Printf("movegen[%s]: %d cases, %d golden moves", v.variant, len(cases), total)
+	}
+}
+
+// encRack encodes a rack given as the variant's letters (plus a blank count) into the
+// index-based genRack the fixtures carry.
+func encRack(rs *rules.Ruleset, letters string, blanks int) genRack {
+	enc, err := rs.Alphabet.Encode(letters)
+	if err != nil {
+		log.Fatalf("movegen: encode rack %q: %v", letters, err)
+	}
+	idx := make([]int, len(enc))
+	for i, b := range enc {
+		idx[i] = int(b)
+	}
+	return genRack{Letters: idx, Blanks: blanks}
+}
+
+// runCase fills a case's Moves by generating on a board holding the given placed
+// tiles (nil = empty board).
+func runCase(s *scrabble.Solver, rs *rules.Ruleset, c *genCase, placed []genTile) {
+	bd := board.New(rs.Rows, rs.Cols)
+	for _, t := range placed {
+		bd.Set(t.Row, t.Col, cellByte(t.Letter, t.Blank))
+	}
+	c.Placed = placed
+	rk := toRack(rs.Size(), c.Rack)
+	moves := s.GenerateMovesOpts(bd, rk, scrabble.Mode(c.Mode), scrabble.PlayOptions{IgnoreCrossWords: c.IgnoreCrossWords})
+	c.Moves = movesOf(moves)
+}
+
+// twoPly reaches a mid-game position by applying the top move of the first standard
+// case that generated one, then generates again with a fresh rack of the same tiles.
+func twoPly(s *scrabble.Solver, rs *rules.Ruleset, cases []genCase) *genCase {
+	for _, c := range cases {
+		if c.IgnoreCrossWords || len(c.Moves) == 0 {
+			continue
+		}
+		placed := c.Moves[0].Tiles
+		next := genCase{Name: "two-ply", Rack: c.Rack, Mode: int(scrabble.Both)}
+		runCase(s, rs, &next, placed)
+		return &next
+	}
+	return nil
+}
+
+// cellByte encodes a board cell the way internal/encoding.Cell does (bits 0-5 hold
+// letter+1, bit 7 marks a blank). Duplicated here because that package is internal
+// to the solver module and cannot be imported.
+func cellByte(letter int, blank bool) byte {
+	v := byte(letter+1) & 0x3f
+	if blank {
+		v |= 0x80
+	}
+	return v
+}
+
+func toRack(size int, r genRack) rack.Rack {
+	rk := rack.New(size)
+	for _, l := range r.Letters {
+		rk.Add(byte(l))
+	}
+	for i := 0; i < r.Blanks; i++ {
+		rk.AddBlank()
+	}
+	return rk
+}
+
+func rulesetOf(rs *rules.Ruleset) genRuleset {
+	lm := make([][]int, rs.Rows)
+	wm := make([][]int, rs.Rows)
+	for r := 0; r < rs.Rows; r++ {
+		lm[r] = make([]int, rs.Cols)
+		wm[r] = make([]int, rs.Cols)
+		for c := 0; c < rs.Cols; c++ {
+			p := rs.Premium(r, c)
+			lm[r][c] = p.LetterMult()
+			wm[r][c] = p.WordMult()
+		}
+	}
+	return genRuleset{
+		Size: rs.Size(), Cols: rs.Cols, Center: rs.Center, RackSize: rs.RackSize,
+		Bingo: rs.Bingo, Values: rs.Values, LetterMult: lm, WordMult: wm,
+	}
+}
+
+func movesOf(ms []scrabble.Move) []genMove {
+	out := make([]genMove, len(ms))
+	for i, m := range ms {
+		out[i] = genMove{Dir: int(m.Dir), Tiles: tilesOf(m.Tiles), Score: m.Score}
+	}
+	return out
+}
+
+func tilesOf(ps []scrabble.Placement) []genTile {
+	out := make([]genTile, len(ps))
+	for i, p := range ps {
+		out[i] = genTile{Row: p.Row, Col: p.Col, Letter: int(p.Letter), Blank: p.Blank}
+	}
+	return out
+}
+
+// emptyCase builds an empty-board case (Moves filled later by runCase).
+func emptyCase(name string, r genRack, mode scrabble.Mode, ignoreCross bool) genCase {
+	return genCase{Name: name, Rack: r, Mode: int(mode), IgnoreCrossWords: ignoreCross}
+}
+
+// englishRack builds a rack from lowercase a-z letters (index = letter-'a').
+func englishRack(letters string, blanks int) genRack {
+	idx := make([]int, 0, len(letters))
+	for _, ch := range letters {
+		idx = append(idx, int(ch-'a'))
+	}
+	return genRack{Letters: idx, Blanks: blanks}
+}
+
+// russianRack builds a rack from the Russian sample letters used above.
+func russianRack(letters string, blanks int) genRack {
+	m := map[rune]int{'а': 0, 'д': 4, 'о': 15, 'р': 17, 'с': 18, 'я': 32}
+	idx := make([]int, 0, len([]rune(letters)))
+	for _, ch := range letters {
+		i, ok := m[ch]
+		if !ok {
+			log.Fatalf("movegen: russianRack: no index for %q", string(ch))
+		}
+		idx = append(idx, i)
+	}
+	return genRack{Letters: idx, Blanks: blanks}
+}
+
+// emitRulesets writes the per-variant static ruleset data (tile values, bag counts, blanks,
+// bingo, rack size) the offline engine mirrors in ui/src/lib/localgame/ruleset.ts, so a TS
+// parity test can pin that hand-copied table to the Go rulesets (scrabble-solver/rules).
+func emitRulesets() {
+	type rsFix struct {
+		Size     int      `json:"size"`
+		RackSize int      `json:"rackSize"`
+		Bingo    int      `json:"bingo"`
+		Blanks   int      `json:"blanks"`
+		Values   []int    `json:"values"`
+		Counts   []int    `json:"counts"`
+		Letters  []string `json:"letters"`
+	}
+	out := map[string]rsFix{}
+	for _, v := range []struct {
+		name string
+		rs   *rules.Ruleset
+	}{
+		{"scrabble_en", rules.English()},
+		{"scrabble_ru", rules.RussianScrabble()},
+		{"erudit_ru", rules.Erudit()},
+	} {
+		letters := make([]string, v.rs.Size())
+		for i := range letters {
+			ch, err := v.rs.Alphabet.Character(byte(i))
+			if err != nil {
+				log.Fatalf("movegen: %s letter %d: %v", v.name, i, err)
+			}
+			letters[i] = strings.ToUpper(ch)
+		}
+		out[v.name] = rsFix{Size: v.rs.Size(), RackSize: v.rs.RackSize, Bingo: v.rs.Bingo, Blanks: v.rs.Blanks, Values: v.rs.Values, Counts: v.rs.Counts, Letters: letters}
+	}
+	dir := filepath.Join("ui", "src", "lib", "localgame", "testdata")
+	if err := os.MkdirAll(dir, 0o755); err != nil {
+		log.Fatalf("movegen: mkdir %s: %v", dir, err)
+	}
+	writeJSON(filepath.Join(dir, "rulesets.json"), out)
+	log.Printf("movegen: wrote %s (3 variants)", filepath.Join(dir, "rulesets.json"))
+}
+
+func writeJSON(path string, v any) {
+	data, err := json.MarshalIndent(v, "", "  ")
+	if err != nil {
+		log.Fatalf("movegen: marshal %s: %v", path, err)
+	}
+	if err := os.WriteFile(path, append(data, '\n'), 0o644); err != nil {
+		log.Fatalf("movegen: write %s: %v", path, err)
+	}
+}

backend/internal/account/email.go

@@ -105,9 +105,10 @@ func (s *EmailService) allowSend(email string) bool {
 
 // issueCode generates a fresh confirm-code and one-tap deeplink token for (accountID,
 // email), replaces any prior pending confirmation, and mails the branded code in
-// locale; purpose selects the email wording and what verifying does. Only the SHA-256
+// locale; purpose selects the email wording and what verifying does. omitLink drops the
-// hashes of the code and token are stored.
+// one-tap deeplink from the email (account deletion, or a login requested from an installed
-func (s *EmailService) issueCode(ctx context.Context, accountID uuid.UUID, email, purpose, locale string) error {
+// PWA). Only the SHA-256 hashes of the code and token are stored.
+func (s *EmailService) issueCode(ctx context.Context, accountID uuid.UUID, email, purpose, locale string, omitLink bool) error {
 	code, codeHash, err := generateCode()
 	if err != nil {
 		return err
@@ -119,11 +120,12 @@ func (s *EmailService) issueCode(ctx context.Context, accountID uuid.UUID, email
 	if err := s.store.replacePendingConfirmation(ctx, accountID, email, codeHash, tokenHash, purpose, s.now().Add(emailCodeTTL)); err != nil {
 		return err
 	}
-	// Account deletion is never a one-tap link (a prefetch or a stray click must not delete
+	// Omit the one-tap deeplink when asked: for a login from an installed PWA (the link would
-	// an account): the delete code is entered in the app only, so the email omits the
+	// open in a separate browser whose minted session cannot reach the PWA), or for account
-	// deeplink and ConfirmByToken refuses a delete token.
+	// deletion (a prefetch or stray click must not delete an account — the delete code is entered
+	// in the app only, and ConfirmByToken refuses a delete token).
 	deeplink := s.confirmURL(token, locale)
-	if purpose == purposeDelete {
+	if purpose == purposeDelete || omitLink {
 		deeplink = ""
 	}
 	msg, err := renderConfirmationEmail(purpose, code, deeplink, s.baseURL, locale)
@@ -175,7 +177,7 @@ func (s *EmailService) RequestCode(ctx context.Context, accountID uuid.UUID, ema
 		}
 		return ErrEmailTaken
 	}
-	return s.issueCode(ctx, accountID, addr, purposeLink, s.accountLocale(ctx, accountID))
+	return s.issueCode(ctx, accountID, addr, purposeLink, s.accountLocale(ctx, accountID), false)
 }
 
 // ConfirmCode verifies code for accountID and email. On success it attaches a
@@ -221,8 +223,11 @@ func (s *EmailService) ConfirmCode(ctx context.Context, accountID uuid.UUID, ema
 // the ordinary returning-user login. The code is mailed to the address, so only its
 // real owner can complete the login. On first contact browserTZ (the client's
 // detected "±HH:MM" UTC offset) seeds the new account's time zone and language its UI
-// language. It returns the target account id for the subsequent LoginWithCode.
+// language. When pwa is set (the request came from an installed PWA) the login email omits the
-func (s *EmailService) RequestLoginCode(ctx context.Context, email, browserTZ, language string) (uuid.UUID, error) {
+// one-tap confirm link — it would open in a separate browser, out of the PWA's reach — so the
+// code is entered in the same window. It returns the target account id for the subsequent
+// LoginWithCode.
+func (s *EmailService) RequestLoginCode(ctx context.Context, email, browserTZ, language string, pwa bool) (uuid.UUID, error) {
 	addr, err := normalizeEmail(email)
 	if err != nil {
 		return uuid.UUID{}, err
@@ -234,7 +239,7 @@ func (s *EmailService) RequestLoginCode(ctx context.Context, email, browserTZ, l
 	if err != nil {
 		return uuid.UUID{}, err
 	}
-	if err := s.issueCode(ctx, acc.ID, addr, purposeLogin, language); err != nil {
+	if err := s.issueCode(ctx, acc.ID, addr, purposeLogin, language, pwa); err != nil {
 		return uuid.UUID{}, err
 	}
 	return acc.ID, nil

backend/internal/account/link.go

@@ -92,7 +92,7 @@ func (s *EmailService) RequestLinkCode(ctx context.Context, accountID uuid.UUID,
 	if !s.allowSend(addr) {
 		return ErrTooManyRequests
 	}
-	return s.issueCode(ctx, accountID, addr, purposeLink, s.accountLocale(ctx, accountID))
+	return s.issueCode(ctx, accountID, addr, purposeLink, s.accountLocale(ctx, accountID), false)
 }
 
 // ConfirmLink verifies code for (accountID, email) and reports the address's
@@ -140,7 +140,7 @@ func (s *EmailService) RequestChangeCode(ctx context.Context, accountID uuid.UUI
 	if !s.allowSend(addr) {
 		return ErrTooManyRequests
 	}
-	return s.issueCode(ctx, accountID, addr, purposeChange, s.accountLocale(ctx, accountID))
+	return s.issueCode(ctx, accountID, addr, purposeChange, s.accountLocale(ctx, accountID), false)
 }
 
 // ConfirmChange verifies code for (accountID, newEmail) and atomically replaces the
@@ -199,7 +199,7 @@ func (s *EmailService) RequestDeleteCode(ctx context.Context, accountID uuid.UUI
 	if !s.allowSend(addr) {
 		return ErrTooManyRequests
 	}
-	return s.issueCode(ctx, accountID, addr, purposeDelete, s.accountLocale(ctx, accountID))
+	return s.issueCode(ctx, accountID, addr, purposeDelete, s.accountLocale(ctx, accountID), false)
 }
 
 // VerifyDeleteCode verifies the account-deletion code against the account's own email and

backend/internal/adminalert/notify.go

@@ -33,21 +33,21 @@ type Notifier struct {
 	complaints ComplaintCounter
 	from       string
 	to         string
-	consoleURL string
 	clock      func() time.Time
 	log        *zap.Logger
 	last       time.Time
 }
 
-// New constructs a Notifier. from and to are the alert sender and recipient(s); consoleURL,
+// New constructs a Notifier. from and to are the alert sender and recipient(s); log may be
-// when non-empty, is the admin-console link included in the email. log may be nil. The
+// nil. The watermark starts at "now", so only items arriving after start-up are reported. The
-// watermark starts at "now", so only items arriving after start-up are reported.
+// digest deliberately carries no admin-console link — an admin URL must never travel in an
-func New(mailer account.Mailer, fb FeedbackCounter, cp ComplaintCounter, from, to, consoleURL string, log *zap.Logger) *Notifier {
+// email, where a mail provider could cache or index it.
+func New(mailer account.Mailer, fb FeedbackCounter, cp ComplaintCounter, from, to string, log *zap.Logger) *Notifier {
 	if log == nil {
 		log = zap.NewNop()
 	}
 	return &Notifier{
-		mailer: mailer, feedback: fb, complaints: cp, from: from, to: to, consoleURL: consoleURL,
+		mailer: mailer, feedback: fb, complaints: cp, from: from, to: to,
 		clock: func() time.Time { return time.Now().UTC() }, log: log, last: time.Now().UTC(),
 	}
 }
@@ -103,10 +103,9 @@ func (n *Notifier) digest(fb, cp int) account.Message {
 		parts = append(parts, fmt.Sprintf("%d new word complaint(s)", cp))
 	}
 	summary := strings.Join(parts, ", ")
+	// No admin-console link in the body: an admin URL must never travel in an email (a mail
+	// provider could cache or index it). The operator opens the console directly.
 	text := summary + "."
-	if n.consoleURL != "" {
-		text += "\n\nOpen the admin console: " + n.consoleURL
-	}
 	return account.Message{
 		From:    n.from,
 		To:      n.to,

backend/internal/adminalert/notify_test.go

@@ -28,7 +28,7 @@ func (m *recordingMailer) Send(_ context.Context, msg account.Message) error {
 
 func TestNotifierSkipsWhenNothingNew(t *testing.T) {
 	mailer := &recordingMailer{}
-	n := New(mailer, fbCounter{0}, cpCounter{0}, "alerts@erudit-game.ru", "op@x.ru", "", nil)
+	n := New(mailer, fbCounter{0}, cpCounter{0}, "alerts@erudit-game.ru", "op@x.ru", nil)
 	n.tick(context.Background())
 	if len(mailer.sent) != 0 {
 		t.Fatalf("sent %d emails, want 0 when nothing is new", len(mailer.sent))
@@ -37,7 +37,7 @@ func TestNotifierSkipsWhenNothingNew(t *testing.T) {
 
 func TestNotifierDigestsNewItems(t *testing.T) {
 	mailer := &recordingMailer{}
-	n := New(mailer, fbCounter{2}, cpCounter{1}, "alerts@erudit-game.ru", "op@x.ru, two@x.ru", "https://erudit-game.ru/_gm", nil)
+	n := New(mailer, fbCounter{2}, cpCounter{1}, "alerts@erudit-game.ru", "op@x.ru, two@x.ru", nil)
 	n.tick(context.Background())
 	if len(mailer.sent) != 1 {
 		t.Fatalf("sent %d emails, want 1 digest", len(mailer.sent))
@@ -49,7 +49,9 @@ func TestNotifierDigestsNewItems(t *testing.T) {
 	if !strings.Contains(msg.Subject, "2 new feedback") || !strings.Contains(msg.Subject, "1 new word complaint") {
 		t.Errorf("digest subject = %q, want the feedback + complaint counts", msg.Subject)
 	}
-	if !strings.Contains(msg.Text, "/_gm") {
+	// The digest must never carry an admin-console link — an admin URL in an email is a leak
-		t.Errorf("digest body = %q, want the console link", msg.Text)
+	// (mail providers cache/index it).
+	if strings.Contains(msg.Text, "/_gm") || strings.Contains(strings.ToLower(msg.Text), "admin console") {
+		t.Errorf("digest body = %q, must not carry an admin-console link", msg.Text)
 	}
 }

backend/internal/engine/endfixture_test.go

@@ -0,0 +1,123 @@
+package engine
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"gitea.iliadenisov.ru/developer/scrabble-solver/rules"
+)
+
+// The offline engine (ui/src/lib/localgame) reproduces the end-of-game rack settlement and the
+// winner rule so a local game finishes with the same scores as the server. These golden fixtures
+// pin the ported pure functions (applyEndAdjustment / winner / rackValue) to the real Go engine.
+// Being in-package, this emitter constructs Game values directly and drives the unexported
+// end-game math on chosen positions.
+
+type endCaseIn struct {
+	Name     string  `json:"name"`
+	Variant  string  `json:"variant"`
+	Reason   string  `json:"reason"`
+	Hands    [][]int `json:"hands"`
+	Scores   []int   `json:"scores"`
+	Resigned []bool  `json:"resigned"`
+	ToMove   int     `json:"toMove"`
+}
+
+type endCaseOut struct {
+	endCaseIn
+	ScoresAfter []int `json:"scoresAfter"`
+	Winner      int   `json:"winner"`
+}
+
+func rulesetFor(variant string) *rules.Ruleset {
+	switch variant {
+	case "scrabble_ru":
+		return rules.RussianScrabble()
+	case "erudit_ru":
+		return rules.Erudit()
+	default:
+		return rules.English()
+	}
+}
+
+func reasonFor(s string) EndReason {
+	switch s {
+	case "out_of_tiles":
+		return EndOutOfTiles
+	case "scoreless":
+		return EndScoreless
+	case "resign":
+		return EndResign
+	case "aborted":
+		return EndAborted
+	}
+	return EndNotOver
+}
+
+func handsBytes(hands [][]int) [][]byte {
+	out := make([][]byte, len(hands))
+	for i, h := range hands {
+		b := make([]byte, len(h))
+		for j, x := range h {
+			b[j] = byte(x)
+		}
+		out[i] = b
+	}
+	return out
+}
+
+// TestEmitEndgameFixtures regenerates ui/src/lib/localgame/testdata/endgame.json. Gated by
+// EMIT_ENGINE_FIXTURES. Regenerate with:
+//
+//	EMIT_ENGINE_FIXTURES=1 go test ./backend/internal/engine -run TestEmitEndgameFixtures
+func TestEmitEndgameFixtures(t *testing.T) {
+	if os.Getenv("EMIT_ENGINE_FIXTURES") == "" {
+		t.Skip("set EMIT_ENGINE_FIXTURES=1 to regenerate ui/src/lib/localgame/testdata/endgame.json")
+	}
+
+	cases := []endCaseIn{
+		{"out-basic", "scrabble_en", "out_of_tiles", [][]int{{}, {0, 1, 2}}, []int{50, 40}, []bool{false, false}, 0},
+		{"out-blank", "scrabble_en", "out_of_tiles", [][]int{{}, {255, 0}}, []int{30, 30}, []bool{false, false}, 0},
+		{"out-erudit-yo", "erudit_ru", "out_of_tiles", [][]int{{}, {6, 32}}, []int{10, 10}, []bool{false, false}, 0},
+		{"out-tie", "scrabble_en", "out_of_tiles", [][]int{{}, {}}, []int{30, 30}, []bool{false, false}, 0},
+		{"out-3p", "scrabble_ru", "out_of_tiles", [][]int{{}, {0, 1}, {2}}, []int{10, 10, 10}, []bool{false, false, false}, 0},
+		{"scoreless", "scrabble_en", "scoreless", [][]int{{0, 1}, {2, 3}}, []int{20, 20}, []bool{false, false}, 0},
+		{"resign-2p", "scrabble_en", "resign", [][]int{{}, {0}}, []int{100, 10}, []bool{true, false}, 1},
+		{"resign-3p", "scrabble_en", "resign", [][]int{{}, {}, {}}, []int{50, 60, 40}, []bool{false, true, false}, 0},
+		{"aborted", "scrabble_en", "aborted", [][]int{{0}, {1}}, []int{40, 30}, []bool{false, false}, 0},
+	}
+
+	out := make([]endCaseOut, 0, len(cases))
+	for _, c := range cases {
+		rs := rulesetFor(c.Variant)
+		scores := append([]int(nil), c.Scores...)
+		g := &Game{
+			rules:    rs,
+			hands:    handsBytes(c.Hands),
+			scores:   scores,
+			resigned: c.Resigned,
+			toMove:   c.ToMove,
+		}
+		reason := reasonFor(c.Reason)
+		g.over = true
+		g.reason = reason
+		g.applyEndAdjustment(reason)
+		out = append(out, endCaseOut{endCaseIn: c, ScoresAfter: g.scores, Winner: g.winner()})
+	}
+
+	dir := filepath.Join("..", "..", "..", "ui", "src", "lib", "localgame", "testdata")
+	if err := os.MkdirAll(dir, 0o755); err != nil {
+		t.Fatalf("mkdir %s: %v", dir, err)
+	}
+	data, err := json.MarshalIndent(map[string]any{"cases": out}, "", "  ")
+	if err != nil {
+		t.Fatalf("marshal: %v", err)
+	}
+	path := filepath.Join(dir, "endgame.json")
+	if err := os.WriteFile(path, append(data, '\n'), 0o644); err != nil {
+		t.Fatalf("write %s: %v", path, err)
+	}
+	t.Logf("wrote %s (%d cases)", path, len(out))
+}

backend/internal/game/helpers_test.go

@@ -69,6 +69,29 @@ func TestHintsRemaining(t *testing.T) {
 	}
 }
 
+func TestHintUnlockLeftSeconds(t *testing.T) {
+	now := time.Now()
+	// A gated vs_ai game on the caller's turn, the robot having moved 10 min ago (turn started then).
+	gated := Game{VsAI: true, ToMove: 0, MoveCount: 2, TurnStartedAt: now.Add(-10 * time.Minute)}
+	cases := []struct {
+		name string
+		g    Game
+		seat int
+		want int
+	}{
+		{"non-vs_ai is open", Game{VsAI: false, ToMove: 0, MoveCount: 2, TurnStartedAt: now.Add(-10 * time.Minute)}, 0, 0},
+		{"not the caller's turn is open", gated, 1, 0},
+		{"human first move (no robot move) is open", Game{VsAI: true, ToMove: 0, MoveCount: 0, TurnStartedAt: now}, 0, 0},
+		{"robot moved 10 min ago leaves 20 min", gated, 0, 20 * 60},
+		{"robot moved past the window is open", Game{VsAI: true, ToMove: 0, MoveCount: 2, TurnStartedAt: now.Add(-40 * time.Minute)}, 0, 0},
+	}
+	for _, c := range cases {
+		if got := hintUnlockLeftSeconds(c.g, c.seat, now); got != c.want {
+			t.Errorf("%s: hintUnlockLeftSeconds = %d, want %d", c.name, got, c.want)
+		}
+	}
+}
+
 func TestAllowedTimeout(t *testing.T) {
 	if !allowedTimeout(24 * time.Hour) {
 		t.Error("24h must be allowed")

backend/internal/game/service.go

@@ -1058,10 +1058,31 @@ func (svc *Service) MarkChangesApplied(ctx context.Context, variant engine.Varia
 	return svc.store.MarkChangesApplied(ctx, variant.String(), version)
 }
 
-// Hint reveals the top-scoring legal play for the requesting player on their
+// hintIdleWindow is how long a vs_ai player must be stuck on a turn (since the robot's last move)
-// turn, spending one hint from their per-game allowance and then their profile
+// before the idle hint unlocks. Mirrors the offline client (lib/hints HINT_GATE_MS = 30 min).
-// wallet. It returns ErrHintsDisabled, ErrNoHintsLeft or ErrNoHintAvailable as
+const hintIdleWindow = 30 * time.Minute
-// appropriate.
+
+// hintUnlockLeftSeconds is the seconds until g's vs_ai idle hint unlocks for seat, measured from now:
+// the robot's last move (the current turn's start, on the human's turn) plus the window, floored at
+// 0 and ceiled to whole seconds. It is 0 for a non-vs_ai game, when it is not seat's turn, or on the
+// human's first move (MoveCount 0, no robot move yet) — the gate is an anti-frustration aid, not a
+// first-move tax. The client anchors a monotonic countdown to it, so a client clock cannot skew it.
+func hintUnlockLeftSeconds(g Game, seat int, now time.Time) int {
+	if !g.VsAI || g.ToMove != seat || g.MoveCount < 1 {
+		return 0
+	}
+	left := g.TurnStartedAt.Add(hintIdleWindow).Sub(now)
+	if left <= 0 {
+		return 0
+	}
+	return int((left + time.Second - 1) / time.Second) // ceil to whole seconds (no math import)
+}
+
+// Hint reveals the top-scoring legal play for the requesting player on their turn. For a human game
+// it spends one hint from the per-game allowance then the profile wallet (ErrHintsDisabled /
+// ErrNoHintsLeft / ErrNoHintAvailable). For a vs_ai game the hint is unlimited and wallet-free but
+// idle-gated from the server clock (ErrHintLocked until the window elapses) and counts toward no
+// hint statistic.
 func (svc *Service) Hint(ctx context.Context, gameID, accountID uuid.UUID) (HintResult, error) {
 	pre, err := svc.store.GetGame(ctx, gameID)
 	if err != nil {
@@ -1080,6 +1101,26 @@ func (svc *Service) Hint(ctx context.Context, gameID, accountID uuid.UUID) (Hint
 	if !pre.HintsAllowed {
 		return HintResult{}, ErrHintsDisabled
 	}
+	if pre.VsAI {
+		// vs_ai: unlimited and wallet-free, but idle-gated from the server clock — and counted toward
+		// no hint statistic. Enforce the gate (the client normally pre-gates from the view's
+		// HintUnlockLeftSeconds; this is the authoritative backstop), then serve the top move without
+		// touching the allowance, the wallet or hints_used.
+		if hintUnlockLeftSeconds(pre, seat, svc.clock()) > 0 {
+			return HintResult{}, ErrHintLocked
+		}
+		unlock := svc.locks.lock(gameID)
+		defer unlock()
+		g, err := svc.liveGame(ctx, pre)
+		if err != nil {
+			return HintResult{}, err
+		}
+		move, ok := g.HintView()
+		if !ok {
+			return HintResult{}, ErrNoHintAvailable
+		}
+		return HintResult{Move: move}, nil
+	}
 	acc, err := svc.accounts.GetByID(ctx, accountID)
 	if err != nil {
 		return HintResult{}, err
@@ -1208,6 +1249,8 @@ func (svc *Service) GameState(ctx context.Context, gameID, accountID uuid.UUID)
 		BagLen:         g.BagLen(),
 		HintsRemaining: hintsRemaining(pre.HintsPerPlayer, pre.Seats[seat].HintsUsed, acc.HintBalance),
 		WalletBalance:  acc.HintBalance,
+		// vs_ai idle-hint gate (seconds left; 0 for a human game / first move / not your turn).
+		HintUnlockLeftSeconds: hintUnlockLeftSeconds(pre, seat, svc.clock()),
 	}, nil
 }
 

backend/internal/game/types.go

@@ -65,6 +65,10 @@ var (
 	ErrNoHintsLeft = errors.New("game: no hints remaining")
 	// ErrNoHintAvailable is returned when the player has no legal play to reveal.
 	ErrNoHintAvailable = errors.New("game: no legal move to suggest")
+	// ErrHintLocked is returned when a vs_ai game's idle hint is still gated (the player has not yet
+	// been stuck the idle window since the robot's last move). The client normally pre-gates from
+	// StateView.HintUnlockLeftSeconds, so this is the authoritative server-clock backstop.
+	ErrHintLocked = errors.New("game: hint is not available yet")
 	// ErrGameLimitReached is returned when an account already holds MaxActiveQuickGames
 	// simultaneous quick games and tries to create another game (quick or by invitation).
 	ErrGameLimitReached = errors.New("game: simultaneous game limit reached")
@@ -240,6 +244,11 @@ type StateView struct {
 	// WalletBalance is the player's global hint-wallet balance alone (HintsRemaining folds
 	// it in with the per-game allowance), so the client keeps the wallet live across games.
 	WalletBalance int
+	// HintUnlockLeftSeconds is, for a vs_ai game on the requesting player's turn, the seconds left
+	// until the idle hint unlocks (the robot's last move plus the idle window, from the server clock);
+	// 0 for the human's first move, when it is not their turn, or a non-vs_ai game. The vs_ai hint is
+	// unlimited and wallet-free; this idle gate replaces the allowance/wallet for it.
+	HintUnlockLeftSeconds int
 }
 
 // HistoryMove is one decoded journal row, independent of any dictionary.

backend/internal/inttest/email_test.go

@@ -206,7 +206,7 @@ func TestEmailLoginFlow(t *testing.T) {
 	svc := account.NewEmailService(account.NewStore(testDB), mailer, "https://erudit-game.ru")
 	email := "login-" + uuid.NewString() + "@example.com"
 
-	accountID, err := svc.RequestLoginCode(ctx, email, "+02:00", "en")
+	accountID, err := svc.RequestLoginCode(ctx, email, "+02:00", "en", false)
 	if err != nil {
 		t.Fatalf("request login code: %v", err)
 	}
@@ -233,7 +233,7 @@ func TestEmailLoginFlow(t *testing.T) {
 	}
 
 	// A second login for the same email is the returning user: same account.
-	if _, err := svc.RequestLoginCode(ctx, email, "", "ru"); err != nil {
+	if _, err := svc.RequestLoginCode(ctx, email, "", "ru", false); err != nil {
 		t.Fatalf("second request: %v", err)
 	}
 	acc2, err := svc.LoginWithCode(ctx, email, sixDigit.FindString(mailer.lastBody))
@@ -255,7 +255,7 @@ func TestEmailLoginProvisionsGuestUntilConfirmed(t *testing.T) {
 	svc := account.NewEmailService(store, mailer, "https://erudit-game.ru")
 	email := "squat-" + uuid.NewString() + "@example.com"
 
-	id, err := svc.RequestLoginCode(ctx, email, "", "en")
+	id, err := svc.RequestLoginCode(ctx, email, "", "en", false)
 	if err != nil {
 		t.Fatalf("request login code: %v", err)
 	}
@@ -279,6 +279,34 @@ func TestEmailLoginProvisionsGuestUntilConfirmed(t *testing.T) {
 	}
 }
 
+// TestEmailLoginPWAOmitsLink: a login requested from an installed PWA (pwa=true) mails only the
+// code — no one-tap confirm link, which would otherwise open in a separate browser out of the
+// PWA's reach. A non-PWA request keeps the link.
+func TestEmailLoginPWAOmitsLink(t *testing.T) {
+	ctx := context.Background()
+	mailer := &capturingMailer{}
+	svc := account.NewEmailService(account.NewStore(testDB), mailer, "https://erudit-game.ru")
+
+	pwaEmail := "pwa-login-" + uuid.NewString() + "@example.com"
+	if _, err := svc.RequestLoginCode(ctx, pwaEmail, "", "en", true); err != nil {
+		t.Fatalf("pwa request login: %v", err)
+	}
+	if sixDigit.FindString(mailer.lastBody) == "" {
+		t.Errorf("pwa login mail must still carry the code, body %q", mailer.lastBody)
+	}
+	if confirmToken.MatchString(mailer.lastBody) {
+		t.Errorf("pwa login mail must omit the one-tap confirm link, body %q", mailer.lastBody)
+	}
+
+	webEmail := "web-login-" + uuid.NewString() + "@example.com"
+	if _, err := svc.RequestLoginCode(ctx, webEmail, "", "en", false); err != nil {
+		t.Fatalf("web request login: %v", err)
+	}
+	if !confirmToken.MatchString(mailer.lastBody) {
+		t.Errorf("non-pwa login mail must keep the one-tap confirm link, body %q", mailer.lastBody)
+	}
+}
+
 // confirmToken extracts the one-tap deeplink token from the /app/#/confirm/<token> link
 // the branded email carries.
 var confirmToken = regexp.MustCompile(`/confirm/([A-Za-z0-9_-]+)`)
@@ -301,7 +329,7 @@ func TestConfirmByTokenLogin(t *testing.T) {
 	svc := account.NewEmailService(store, mailer, "https://erudit-game.ru")
 	email := "tok-login-" + uuid.NewString() + "@example.com"
 
-	id, err := svc.RequestLoginCode(ctx, email, "", "en")
+	id, err := svc.RequestLoginCode(ctx, email, "", "en", false)
 	if err != nil {
 		t.Fatalf("request login: %v", err)
 	}
@@ -382,7 +410,7 @@ func TestEmailAccountSeedsDisplayName(t *testing.T) {
 	svc := account.NewEmailService(store, &capturingMailer{}, "https://erudit-game.ru")
 	local := "kaya-" + uuid.NewString()[:8]
 
-	id, err := svc.RequestLoginCode(ctx, local+"@example.com", "", "en")
+	id, err := svc.RequestLoginCode(ctx, local+"@example.com", "", "en", false)
 	if err != nil {
 		t.Fatalf("request login: %v", err)
 	}

backend/internal/robot/strategyfixture_test.go

@@ -0,0 +1,146 @@
+package robot
+
+import (
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"strconv"
+	"testing"
+
+	"scrabble/backend/internal/engine"
+)
+
+// The client-side offline robot (ui/src/lib/robot) reproduces the robot's move choice
+// so a local vs_ai game plays the same way as the server. These golden fixtures pin that
+// TS port to the real Go strategy. Being in-package, this emitter can exercise the
+// unexported mix / playToWin / deviates / selectMove that the port mirrors.
+
+type mixCase struct {
+	Seed  string `json:"seed"`
+	Salt  string `json:"salt"`
+	Nums  []int  `json:"nums"`
+	Value string `json:"value"` // the mix() uint64, as a decimal string (exceeds JS safe ints)
+}
+
+type decisionCase struct {
+	Seed       string `json:"seed"`
+	MoveCount  int    `json:"moveCount"`
+	MyScore    int    `json:"myScore"`
+	OppScore   int    `json:"oppScore"`
+	CandScores []int  `json:"candScores"`
+	RackLen    int    `json:"rackLen"`
+	BagLen     int    `json:"bagLen"`
+	PlayToWin  bool   `json:"playToWin"`
+	Win        bool   `json:"win"` // the per-turn intent after the deviate flip
+	Kind       string `json:"kind"`
+	Index      int    `json:"index"` // chosen candidate index for a play, else -1
+}
+
+type strategyFixture struct {
+	PlayToWinPercent int            `json:"playToWinPercent"`
+	Mix              []mixCase      `json:"mix"`
+	Decisions        []decisionCase `json:"decisions"`
+}
+
+// scenario is one selectMove situation exercised across several seeds.
+type scenario struct {
+	moveCount, myScore, oppScore, rackLen, bagLen int
+	cands                                         []int
+}
+
+// TestEmitStrategyFixtures regenerates ui/src/lib/robot/testdata/strategy.json. It is
+// gated by EMIT_STRATEGY_FIXTURES so a normal `go test` skips it; the committed output is
+// what the TS parity test consumes. Regenerate with:
+//
+//	EMIT_STRATEGY_FIXTURES=1 go test ./backend/internal/robot -run TestEmitStrategyFixtures
+func TestEmitStrategyFixtures(t *testing.T) {
+	if os.Getenv("EMIT_STRATEGY_FIXTURES") == "" {
+		t.Skip("set EMIT_STRATEGY_FIXTURES=1 to regenerate ui/src/lib/robot/testdata/strategy.json")
+	}
+
+	seeds := []int64{1, 42, -7, 1000003, 9999999999, 123456789, -123456789}
+
+	mixCases := []mixCase{}
+	addMix := func(seed int64, salt string, nums ...int) {
+		mixCases = append(mixCases, mixCase{
+			Seed:  strconv.FormatInt(seed, 10),
+			Salt:  salt,
+			Nums:  append([]int{}, nums...),
+			Value: strconv.FormatUint(mix(seed, salt, nums...), 10),
+		})
+	}
+	for _, sd := range seeds {
+		addMix(sd, "win")
+		addMix(sd, "deviate", 0)
+		addMix(sd, "deviate", 7)
+	}
+
+	scenarios := []scenario{
+		{3, 40, 55, 7, 20, []int{30, 12, 8}},   // behind, mid-game
+		{10, 120, 90, 7, 8, []int{25, 18, 5}},  // ahead, late
+		{1, 0, 0, 7, 30, []int{60, 30, 15, 7}}, // first move, big spread
+		{20, 200, 40, 5, 2, []int{50, 20}},     // big lead, bag near empty (no deviate)
+		{5, 30, 30, 7, 14, []int{20, 20, 20}},  // equal margins (tie-break)
+		{8, 50, 60, 7, 20, []int{}},            // no play, bag can refill -> exchange
+		{8, 50, 60, 3, 2, []int{}},             // no play, bag can't refill -> pass
+		{15, 300, 10, 7, 6, []int{80, 40, 10}}, // overshoots the band -> nearest to +30
+	}
+
+	decisions := []decisionCase{}
+	for _, sd := range seeds {
+		for _, sc := range scenarios {
+			cands := make([]engine.MoveRecord, len(sc.cands))
+			for i, s := range sc.cands {
+				cands[i] = engine.MoveRecord{Score: s, Player: i}
+			}
+			rack := make([]string, sc.rackLen)
+			for i := range rack {
+				rack[i] = "a"
+			}
+
+			ptw := playToWin(sd)
+			win := ptw
+			if deviates(sd, sc.moveCount, sc.bagLen) {
+				win = !win
+			}
+			d := selectMove(cands, sc.myScore, sc.oppScore, win, defaultBand, rack, sc.bagLen)
+
+			kind, index := "pass", -1
+			switch d.kind {
+			case decidePlay:
+				kind, index = "play", d.move.Player
+			case decideExchange:
+				kind = "exchange"
+			}
+
+			decisions = append(decisions, decisionCase{
+				Seed:       strconv.FormatInt(sd, 10),
+				MoveCount:  sc.moveCount,
+				MyScore:    sc.myScore,
+				OppScore:   sc.oppScore,
+				CandScores: append([]int{}, sc.cands...),
+				RackLen:    sc.rackLen,
+				BagLen:     sc.bagLen,
+				PlayToWin:  ptw,
+				Win:        win,
+				Kind:       kind,
+				Index:      index,
+			})
+		}
+	}
+
+	fx := strategyFixture{PlayToWinPercent: playToWinPercent, Mix: mixCases, Decisions: decisions}
+	dir := filepath.Join("..", "..", "..", "ui", "src", "lib", "robot", "testdata")
+	if err := os.MkdirAll(dir, 0o755); err != nil {
+		t.Fatalf("mkdir %s: %v", dir, err)
+	}
+	data, err := json.MarshalIndent(fx, "", "  ")
+	if err != nil {
+		t.Fatalf("marshal: %v", err)
+	}
+	path := filepath.Join(dir, "strategy.json")
+	if err := os.WriteFile(path, append(data, '\n'), 0o644); err != nil {
+		t.Fatalf("write %s: %v", path, err)
+	}
+	t.Logf("wrote %s (%d mix, %d decisions)", path, len(mixCases), len(decisions))
+}

backend/internal/server/banner.go

@@ -8,6 +8,7 @@ import (
 
 	"scrabble/backend/internal/account"
 	"scrabble/backend/internal/ads"
+	"scrabble/backend/internal/engine"
 	"scrabble/backend/internal/notify"
 )
 
@@ -56,9 +57,34 @@ func (s *Server) profileResponse(ctx context.Context, acc account.Account) profi
 	r := profileResponseFor(acc)
 	r.Banner = s.bannerFor(ctx, acc)
 	s.fillLinkedIdentities(ctx, &r, acc.ID)
+	r.DictVersions = s.currentDictVersions()
 	return r
 }
 
+// currentDictVersions reports the current dictionary version of every game variant with a
+// resident dictionary, as engine.Variant stable labels. It backs profileResponse.DictVersions
+// so an offline-capable client preloads the matching dawg per variant off the cold-start
+// profile. A variant without a loaded dictionary is omitted (Registry.Latest reports
+// ErrUnknownVariant); the returned slice is nil only when no variant is resident.
+func (s *Server) currentDictVersions() []dictVersion {
+	if s.registry == nil {
+		return nil // no dictionary registry wired (e.g. a minimal test server): advertise none
+	}
+	variants := []engine.Variant{engine.VariantEnglish, engine.VariantRussianScrabble, engine.VariantErudit}
+	out := make([]dictVersion, 0, len(variants))
+	for _, v := range variants {
+		version, _, err := s.registry.Latest(v)
+		if err != nil {
+			continue
+		}
+		out = append(out, dictVersion{Variant: v.String(), Version: version})
+	}
+	if len(out) == 0 {
+		return nil
+	}
+	return out
+}
+
 // fillLinkedIdentities sets the profile's confirmed email address and platform-linked
 // flags from the account's identities, so the client offers the right link / unlink /
 // change-email controls. A read failure leaves them zero (no controls), logged as a

backend/internal/server/dto.go

@@ -63,6 +63,20 @@ type profileResponse struct {
 	Email          string `json:"email"`
 	TelegramLinked bool   `json:"telegram_linked"`
 	VkLinked       bool   `json:"vk_linked"`
+	// DictVersions lists the current dictionary version per game variant (engine.Variant
+	// stable labels). An installed PWA preparing for offline play reads it to preload the
+	// right dawg per enabled variant off this cold-start response, without an extra request.
+	// Filled outside the pure projection (it reads the dictionary registry), so it is empty
+	// for callers that build the DTO without a Server. See Server.profileResponse.
+	DictVersions []dictVersion `json:"dict_versions,omitempty"`
+}
+
+// dictVersion pairs a game variant's stable label (engine.Variant.String) with its current
+// dictionary version. profileResponse.DictVersions carries the set so an offline-capable
+// client preloads the matching dawg per variant.
+type dictVersion struct {
+	Variant string `json:"variant"`
+	Version string `json:"version"`
 }
 
 // tileDTO is one placed (or to-place) tile.
@@ -149,13 +163,16 @@ type alphabetEntryDTO struct {
 // stateDTO is a player's view of a game. Rack carries wire alphabet indices (a
 // blank is engine.BlankIndex). Alphabet is present only when the request asked for it.
 type stateDTO struct {
-	Game           gameDTO            `json:"game"`
+	Game           gameDTO `json:"game"`
-	Seat           int                `json:"seat"`
+	Seat           int     `json:"seat"`
-	Rack           []int              `json:"rack"`
+	Rack           []int   `json:"rack"`
-	BagLen         int                `json:"bag_len"`
+	BagLen         int     `json:"bag_len"`
-	HintsRemaining int                `json:"hints_remaining"`
+	HintsRemaining int     `json:"hints_remaining"`
-	WalletBalance  int                `json:"wallet_balance"`
+	WalletBalance  int     `json:"wallet_balance"`
-	Alphabet       []alphabetEntryDTO `json:"alphabet,omitempty"`
+	// HintUnlockLeftSeconds is the vs_ai idle-hint gate: seconds until the hint unlocks (0 for a human
+	// game / first move / not your turn). The client anchors a monotonic countdown to it.
+	HintUnlockLeftSeconds int                `json:"hint_unlock_left_seconds"`
+	Alphabet              []alphabetEntryDTO `json:"alphabet,omitempty"`
 }
 
 // matchDTO reports whether the caller has been paired into a game.
@@ -301,12 +318,13 @@ func stateDTOFrom(v game.StateView, includeAlphabet bool) (stateDTO, error) {
 		return stateDTO{}, err
 	}
 	dto := stateDTO{
-		Game:           gameDTOFromGame(v.Game),
+		Game:                  gameDTOFromGame(v.Game),
-		Seat:           v.Seat,
+		Seat:                  v.Seat,
-		Rack:           rack,
+		Rack:                  rack,
-		BagLen:         v.BagLen,
+		BagLen:                v.BagLen,
-		HintsRemaining: v.HintsRemaining,
+		HintsRemaining:        v.HintsRemaining,
-		WalletBalance:  v.WalletBalance,
+		WalletBalance:         v.WalletBalance,
+		HintUnlockLeftSeconds: v.HintUnlockLeftSeconds,
 	}
 	if includeAlphabet {
 		tab, err := engine.AlphabetTable(v.Game.Variant)

backend/internal/server/handlers.go

@@ -239,6 +239,9 @@ func statusForError(err error) (int, string) {
 		return http.StatusConflict, "no_hint_available"
 	case errors.Is(err, game.ErrHintsDisabled), errors.Is(err, game.ErrNoHintsLeft):
 		return http.StatusConflict, "hint_unavailable"
+	case errors.Is(err, game.ErrHintLocked):
+		// A vs_ai idle hint is still gated (the server-clock backstop); the client shows the lock.
+		return http.StatusConflict, "hint_locked"
 	case errors.Is(err, engine.ErrIllegalPlay), errors.Is(err, engine.ErrTilesNotOnRack), errors.Is(err, engine.ErrGameOver):
 		return http.StatusUnprocessableEntity, "illegal_play"
 	case errors.Is(err, account.ErrEmailTaken), errors.Is(err, account.ErrIdentityTaken):

backend/internal/server/handlers_auth.go

@@ -174,6 +174,10 @@ type emailRequest struct {
 	Email     string `json:"email"`
 	BrowserTZ string `json:"browser_tz"`
 	Language  string `json:"language"`
+	// Pwa marks a request from an installed PWA (standalone display mode): the login email then
+	// omits the one-tap confirm link so the code is typed in the same window (the link would open
+	// in a separate browser whose session cannot reach the PWA). See EmailService.RequestLoginCode.
+	Pwa bool `json:"pwa"`
 }
 
 // handleEmailRequest issues a login confirm-code to the email. It always reports
@@ -185,7 +189,7 @@ func (s *Server) handleEmailRequest(c *gin.Context) {
 		abortBadRequest(c, "email is required")
 		return
 	}
-	if _, err := s.emails.RequestLoginCode(c.Request.Context(), req.Email, req.BrowserTZ, req.Language); err != nil {
+	if _, err := s.emails.RequestLoginCode(c.Request.Context(), req.Email, req.BrowserTZ, req.Language, req.Pwa); err != nil {
 		s.abortErr(c, err)
 		return
 	}

docs/ARCHITECTURE.md

@@ -244,7 +244,9 @@ arrive from a platform rather than completing a mandatory registration).
   256-bit token stored only as its SHA-256, 12-hour TTL): a login mints a session in the
   browser that opens it (magic-link), a link confirms the identity and emits a `notify`
   profile-refresh to the in-app session, a change switches the account's email in place,
-  and a would-be merge is deferred to the interactive flow. The confirm runs on load; the token rides the URL fragment (never
+  and a would-be merge is deferred to the interactive flow. A login requested from an installed **PWA** omits the deeplink
+  entirely — its email carries the code only, typed in the same window, since the link would open
+  in a separate browser whose minted session cannot reach the PWA. The confirm runs on load; the token rides the URL fragment (never
   sent to the server), so a plain link prefetch cannot reach it, and the manual
   six-digit code is the fallback if an aggressive scanner runs the page. An
   **email-login** account is created flagged `is_guest` and stays reapable until the
@@ -1041,7 +1043,9 @@ link — misses the event; while an add-email confirmation is pending the client
   (`internal/adminalert`, started from `main`) emails the operator (`ADMIN_EMAIL`, from a
   distinct `SMTP_RELAY_ADMIN_FROM`) when new player feedback or word complaints arrive,
   **coalescing** a burst into one digest per interval; both recipients may be several
-  comma-separated addresses. Both paths are inert unless configured.
+  comma-separated addresses. The digest carries **no admin-console link** — an admin URL must
+  never travel in an email, where a mail provider could cache or index it; the operator opens the
+  console directly. Both paths are inert unless configured.
 - Per-request server-side timing via gin middleware from day one (the access log
   carries method, route, status, latency and the active trace id). A
   client-measured RTT piggybacked on the next request is a later enhancement.
@@ -1233,7 +1237,76 @@ origin, so the test contour canonicalises to production instead of being indexed
 separate site; the SPA shell is `noindex`, and the landing always boots in Russian (no
 browser-language detection — crawlers render with arbitrary languages). The favicon set,
 `og-image.png` and `robots.txt` ship unhashed from `ui/public/` (generated by
-`assets/icons/`, same tile design as the VK loader). Hash-named `/assets/*` are served
+`assets/icons/`, same tile design as the VK loader). On the web (`/app/`) the SPA is an installable **PWA**:
+`manifest.webmanifest` ships unhashed from `ui/public/`, while the **service worker** (`sw.js`) is
+built from `ui/src/sw.ts` by **vite-plugin-pwa** (injectManifest strategy) — the client registers it
+**web-only**, never inside a Mini App or the mock build (the plugin is disabled there entirely). It
+**precaches the app shell and the hashed assets** (Workbox) so an installed PWA cold-launches with
+no network. Shell **navigations are network-first** — the fresh `no-cache` shell is fetched from the
+server (so a new deploy is picked up on the very next launch, not the one after), falling back to the
+precached shell only when the network is unreachable or too slow; the immutable hashed assets stay
+cache-first, and the hash router resolves the route client-side. This navigation route is registered
+**before** the precache route on purpose: Workbox matches in registration order, and the precache
+route (its `directoryIndex` is `index.html`) would otherwise shadow it and serve the shell
+cache-first — the old build's version until a second load. The landing page and the conditional
+polyfill bundle are excluded, and the Connect stream and runtime API POSTs are never precached nor
+intercepted, so the live app is never served stale. This satisfies Chromium's installability requirement (a registered SW, needed
+for install on Android) and powers the opt-in **offline mode** (in progress): a deliberate, device-scoped Settings
+toggle — distinct from the transient gateway-reachability signal — that tints the header blue with
+an *Offline* chip and confines play to on-device `vs_ai` games. The **offline lobby lists only those
+device-local games** (reconstructed by replaying the IndexedDB move journal) and its New-vs-AI entry
+creates one through the in-browser engine — the same game screen then drives it, the robot replying
+locally; online-only affordances (the Stats tab, the random-opponent option) are disabled
+or hidden, and New Game's *with friends* becomes the entry to **local pass-and-play (hotseat)**.
+A hotseat game is a device-local **2-4 human** game built through the same engine (`hotseat` +
+per-seat/host PIN locks on the record; the seats carry names but no accounts). A **mandatory host
+(referee) PIN** gates the roster at creation and, in-game, the referee overrides — **skip** the
+current turn, **exclude** a player (a forced seat resign, `resignSeat`) or **terminate** the game
+(deleted, no winner/loser); each seat may also carry its own **optional PIN** that withholds its rack
+(the board stays visible — only the tray is gated) until it is entered, so players pass the device
+around freely and lock a seat only against a distrusted tablemate. The unlock is **per turn**
+(re-locks on advance). PINs are a **social lock, not cryptography** — a salted SHA-256 kept only in
+the device record (`lib/pin`); a 4-digit PIN is trivially brute-forceable and the racks live in
+client memory regardless, so they defeat a casual glance, not a determined peek. A hotseat game is
+**not `vs_ai`**: hints (the freed control becomes the host button) and chat/self-resign are gone, and
+its lobby card — active *and* finished — is master-PIN-gated to delete (so the last mover cannot
+instantly wipe it); a naturally finished game is saved with its result like any local game. A `vs_ai`
+hint (online and offline alike) is unlimited and wallet-free but idle-gated
+(unlocked ~30 min into a stuck turn), and counts toward no hint statistic. The **source** reports the
+**seconds left** (`hint_unlock_left_seconds` on the game view) — computed by the **backend from the
+server clock** online (which also enforces the gate, returning `hint_locked` for an early request),
+and by the offline source from the device clock (persisted, capped at the window). The **client
+anchors a MONOTONIC countdown** (`performance.now()`, `lib/hints`) to that seconds-left when it lands
+(on load, and to the full window when the robot moves), so a client clock change cannot skew it, and
+a relaunch re-reads a fresh value so the wait is not forgotten. To have data ready before the switch, the **Profile advertises the current dictionary
+version per variant** (`dict_versions`,
+filled from the registry on the existing cold-start profile request — no extra round-trip), and an
+eligible installed PWA (standalone web + confirmed email) **background-preloads** those dictionaries
+— on lobby entry and on a variant-preference change — through the same three-tier loader, retried
+with backoff and honouring the session miss-breaker; the move generator, the loader and the preload
+orchestration stay in lazy chunks. A first-lobby preload failure shows a *poor-connection* notice in
+the ad-banner slot. Flipping the Settings toggle **to** offline runs that same cache-first fetch
+bounded by a ~5 s UI wait (`raceOfflineReady` + the lazy `dict/offlineready`): it enters offline only
+once every enabled variant is ready, otherwise it stays online with a *needs internet* note while the
+fetch finishes in the background (the next flip is then instant). A **cold launch already in offline
+mode** boots from the persisted session and
+profile (the profile is saved on every online adopt/refresh) — `bootstrap` skips the session
+adoption and profile fetch that would otherwise hang with no network, and lands straight in the
+offline lobby; without a cached profile (an install that was never online) it drops the sticky flag
+and boots online instead. Beyond the sticky toggle the app **auto-detects connectivity**: the
+reactive flag carries an *auto* bit, so a self-entered offline (no network) is transient
+(session-only, never persisted) and self-heals to online when the network returns, while a deliberate
+one (the toggle, or the cold-start dialog's *Switch*) persists. At cold start `navigator.onLine ===
+false` enters offline for the session; otherwise a single bounded reachability probe (a `profile.get`,
+~3 s) decides — success boots online, a timeout on an eligible install raises a *No connection* dialog
+(*Switch* = sticky offline, *Wait for network* = boot online with the reachability watcher retrying).
+Mid-session the `window` `online`/`offline` events drive it — `offline` auto-enters, `online`
+re-verifies reachability before returning — backed by a `navigator.onLine` poll because those events
+are unreliable on some platforms (notably iOS PWAs). Offline is a real **transport kill switch**
+(every gateway call is refused, so no traffic leaks); the reachability probe is the one call exempt
+from it (it is the return-to-online mechanism), and the transient reachability watcher is suppressed
+while offline. The gateway registers the `.webmanifest` MIME type
+in-process (the distroless image has no `/etc/mime.types`). Hash-named `/assets/*` are served
 `immutable` (a relaunch is a cache hit, not a re-download); the HTML shells are
 `no-cache` so a new deploy is picked up — both containers apply the same caching. An
 in-compose **caddy** is the contour's edge: it owns a single `/_gm` Basic-Auth and

docs/FUNCTIONAL.md

@@ -21,7 +21,8 @@ Settings also pick the board's bonus-label style (beginner / classic / none). A
 costs nothing when the rack has no legal move. The word-check accepts only the
 variant's alphabet, remembers answers within the session and rate-limits repeats.
 A public **landing page** at the site root introduces the game, switches language and
-theme, and links to the Telegram game channel and the VK Mini App; the game itself runs at
+theme, and links to the Telegram game channel, the VK Mini App and the **web version**
+(`/app/`) — each under a caption (Telegram / VK / Веб-версия); the game itself runs at
 `/app/` (web), `/telegram/` (the Telegram Mini App) and `/vk/` (the VK Mini App). The landing's theme is ephemeral
 (it follows the system scheme, not the saved preference); its language choice is saved. The
 landing always opens in **Russian** — the browser language is never auto-detected (crawlers
@@ -31,6 +32,11 @@ nondeterministic); a saved 🌐 choice still wins. The page carries a static Rus
 pinned to the production origin, JSON-LD, the favicon set and `robots.txt`), while the SPA
 shell is `noindex` — the landing is the only indexable page.
 
+On the plain web the client is an **installable PWA**: a logged-out player sees an install
+call-to-action under the login form (and at the bottom of Settings) that installs the app to the
+home screen / desktop in one tap where the browser supports it (Chromium), or shows manual
+Add-to-Home-Screen steps on iOS Safari; it is hidden once installed and inside the Mini Apps.
+
 ### First-run onboarding
 The first time a player opens the app it walks them through the interface with a light
 **coachmark overlay**: a dimmed layer draws one hint bubble at a time, each pointing — with a
@@ -70,7 +76,9 @@ per address), so a mistyped address or an impatient tap cannot flood an inbox. T
 also carries a **one-tap link** that confirms the address — or signs the player straight
 in — in a single tap; opening it in another browser reflects in the app at once, and a
 mail scanner that merely fetches the link cannot reach it — the token rides the URL
-fragment, which is never sent to the server.
+fragment, which is never sent to the server. A sign-in requested from an **installed PWA** omits
+this link: the email carries only the code, entered in the same window, since the link would open
+in a separate browser the app cannot reach.
 Telegram runs a **single bot**: every player uses
 the same bot, and all of its chat and out-of-app notifications are written in the
 player's own **interface language** (en/ru). A separate optional **promo bot** can run alongside the
@@ -207,7 +215,16 @@ unlimited and offers a complaint on any result; for a word it finds, it also lin
 external reference dictionary (gramota.ru for Russian games, scrabblewordfinder.org for
 English) to look it up. Hints are governed per game —
 whether they are allowed and how many each player starts with — and draw on a
-personal hint wallet once the per-game allowance is spent. The game ends when the
+personal hint wallet once the per-game allowance is spent. Against the robot
+(**vs_ai**) hints are instead **unlimited and wallet-free**, but idle-gated as an
+anti-frustration aid: one unlocks only after the player has been **stuck ~30 minutes
+on a turn** (timed from the robot's last move; the very first move, before the robot
+has played, is exempt). While gated the hint button carries a small **🔒 lock** and a
+tap shows how long remains; the lock lifts live at the mark. The same gate applies **online and
+offline**: the countdown runs on a **steady in-app timer**, not the device clock, so changing the
+clock cannot skew it, and a relaunch re-reads the remaining time so a stuck turn is not forgotten.
+Online the **server enforces** it from its own clock (which the player cannot touch); a vs_ai hint
+counts toward no hint statistic. The game ends when the
 bag empties and a player clears their rack, after 6 consecutive scoreless turns,
 by resignation, or by the per-game move timeout (5 minutes to 24 hours, default
 24 hours): a missed turn auto-resigns, except while the player is inside their
@@ -248,6 +265,44 @@ the same occasional move against its plan that fades out by the endgame), and ch
 add-friend are off. AI games are **practice** — they never count toward a player's
 statistics.
 
+### Offline mode
+An installed web PWA signed in with a confirmed email can switch to a deliberate **offline mode**
+(Settings → Play mode). Offline, the app never touches the network: the header turns blue with an
+*Offline* chip, the lobby lists only the games stored on the device, and online-only surfaces are
+disabled or hidden (the Stats tab; the *random opponent* option in New Game).
+A New Game against the robot creates a device-local **vs_ai** game — it
+plays entirely in the browser with no backend. Local games are kept on the device, visible only in
+offline mode, and never sync to the account. So a game can be created and played with no connection,
+the app quietly preloads the dictionaries for the player's enabled variants while still online, and
+(once installed) launches from a precached shell even with no network. Switching **to** offline first
+checks that the enabled variants' dictionaries are on the device — if any are missing it fetches them
+and waits briefly, and if they cannot be readied it stays online with a short *needs internet* note
+(the download keeps running in the background, so a later switch is instant). The mode is
+device-scoped and sticky across launches.
+
+Offline, New Game's **with friends** starts a **local pass-and-play** game for 2-4 people sharing one
+device. You first set a **host (leader) password** — a 4-digit PIN entered on a lock-screen-style
+keypad; until it is set the player rows stay locked. The app then asks whether you are playing too —
+if so you take the first seat with your profile name. You name each player (2 to 4; add or remove
+rows, where a removal asks for the leader password) and may give any seat its **own optional PIN**.
+During the game the board is always visible, but a PIN-locked seat shows an **Unlock** button in place
+of its rack until its owner enters the PIN — so the device passes hand to hand and only a protected
+seat hides its letters; the lock returns each turn. The **leader** (the host button in the game) can,
+with the leader password, **skip** the current player's turn, **remove** a player, or **end the game
+early** — an early end discards the game with no winner or loser. Hints and chat are off in a
+pass-and-play game. A game that finishes normally is saved to the offline lobby like any other;
+deleting any pass-and-play game — running or finished — from the lobby asks for the leader password,
+so no one can wipe a game the moment they have moved.
+
+The app also **enters offline mode on its own** when it cannot reach the network. On a cold launch
+with no connection it switches to offline for that session; when the device is online but the gateway
+stays silent for a few seconds it asks first — *No connection. Switch to offline mode?*, with
+**Switch** (go offline) or **Wait for network** (keep retrying online). While the app is open, losing
+the network — airplane mode — switches to offline automatically, and restoring it returns online by
+itself. A self-entered offline is temporary: it reverts to online the moment the network is back, and
+the next launch re-checks. A **deliberate** offline — the Settings toggle, or **Switch** in that
+dialog — is the player's choice: it is kept, and never undone automatically.
+
 ### Social: friends, block, chat, nudge
 Become friends in two ways: redeem a **one-time code** the other player issues (six
 digits, valid for twelve hours), or send a **request to someone you have played

docs/FUNCTIONAL_ru.md

@@ -22,7 +22,8 @@ top-1 подсказку, безлимитную проверку слова с
 Проверка слова принимает только алфавит варианта, запоминает ответы в рамках сессии
 и ограничивает частоту повторов.
 Публичная **посадочная страница** в корне сайта представляет игру, переключает язык и
-тему и ведёт в Telegram-канал игры и в VK Mini App; сама игра живёт по адресам
+тему и ведёт в Telegram-канал игры, в VK Mini App и в **веб-версию** (`/app/`) — каждая под
+подписью (Telegram / VK / Веб-версия); сама игра живёт по адресам
 `/app/` (веб), `/telegram/` (Telegram Mini App) и `/vk/` (VK Mini App). Тема на странице эфемерна (берётся из
 системной настройки, а не из сохранённой), выбор языка сохраняется. Страница всегда
 открывается на **русском** — язык браузера не определяется автоматически (роботы
@@ -33,6 +34,11 @@ Open Graph, которую используют превью ссылок в Tel
 продакшен-домена, JSON-LD, набор favicon и `robots.txt`), а оболочка SPA помечена
 `noindex` — индексируется только посадочная страница.
 
+В обычном вебе клиент — **устанавливаемое PWA**: незалогиненный игрок видит призыв к установке
+под формой входа (и внизу «Настроек»), который в один тап ставит приложение на рабочий стол
+(домашний экран) там, где браузер это умеет (Chromium), либо показывает ручные шаги
+«На экран „Домой“» в Safari на iOS; он скрыт после установки и внутри Mini App.
+
 ### Первый запуск: онбординг
 При первом открытии приложения игрока один раз проводят по интерфейсу лёгким
 **coachmark-оверлеем**: затемнённый слой показывает по одной подсказке-«облачку» за раз, каждое
@@ -74,7 +80,9 @@ launch-параметрам VK (их проверяет gateway), и при пе
 не завалили почтовый ящик. В письме также есть **ссылка одного нажатия**, которая подтверждает
 адрес — или сразу выполняет вход — в один тап; открытие её в другом браузере тут же отражается в
 приложении, а почтовый сканер, который просто загружает ссылку, до токена не дотянется —
-он едет в URL-фрагменте, который не уходит на сервер.
+он едет в URL-фрагменте, который не уходит на сервер. Вход, запрошенный из **установленного
+PWA**, эту ссылку не содержит: в письме только код, который вводится в том же окне (ссылка
+открылась бы в отдельном браузере, недоступном приложению).
 Telegram держит **единого бота**: все игроки пользуются одним
 и тем же ботом, а весь его чат и внеприложенческие уведомления пишутся на **языке
 интерфейса** самого игрока (en/ru). Рядом с основным может работать отдельный опциональный
@@ -214,7 +222,16 @@ e-mail) либо ввод фразы. Активные игры форфейтя
 внешний справочный словарь (gramota.ru для русских игр, scrabblewordfinder.org для английских),
 чтобы его посмотреть. Подсказки управляются настройками
 партии — разрешены ли они и сколько их у каждого игрока на старте — и расходуют
-личный кошелёк подсказок после исчерпания внутриигрового лимита. Партия
+личный кошелёк подсказок после исчерпания внутриигрового лимита. Против робота
+(**vs_ai**) подсказки, наоборот, **безлимитны и без кошелька**, но с idle-гейтом как
+анти-фрустрация: подсказка открывается, только когда игрок **застрял на ходу ~30 минут**
+(отсчёт от последнего хода робота; самый первый ход, до хода робота, исключён). Пока гейт
+закрыт, кнопка подсказки несёт маленький **🔒 замок**, а тап показывает, сколько осталось;
+замок снимается вживую в нужный момент. Один и тот же гейт работает **онлайн и офлайн**: отсчёт
+идёт по **ровному внутриигровому таймеру**, а не по системным часам, поэтому их перевод его не
+собьёт, а повторный вход перечитывает остаток — застрявший ход не забывается. Онлайн гейт
+**принуждает сервер** по своим часам (их игрок не тронет); vs_ai-подсказка не учитывается ни в
+одной статистике подсказок. Партия
 завершается, когда мешок пуст и игрок выложил стойку, после 6 подряд бесплодных
 ходов, по сдаче, либо по таймауту хода (от 5 минут до 24 часов, дефолт 24 часа):
 пропущенный ход означает авто-сдачу, кроме как когда игрок внутри своего
@@ -253,6 +270,45 @@ e-mail) либо ввод фразы. Активные игры форфейтя
 паузы), сохраняет ту же силу (по-прежнему играет на победу лишь примерно в 40% партий, с теми же
 редкими ходами вопреки плану, затухающими к эндшпилю), а чат, nudge и «добавить в друзья» выключены. Партии с ИИ — это **тренировка**: они не идут в статистику игрока.
 
+### Офлайн-режим
+Установленный веб-PWA со входом по подтверждённой почте может переключиться в осознанный
+**офлайн-режим** (Настройки → Режим игры). В офлайне приложение не обращается к сети: шапка синеет с
+меткой *Офлайн*, лобби показывает только сохранённые на устройстве игры, а сетевые поверхности
+отключены или скрыты (вкладка Статистика; вариант «случайный соперник» в Новой игре).
+Новая игра против робота создаёт локальную **vs_ai**-игру — он ходит
+целиком в браузере без бэкенда. Локальные игры хранятся на устройстве, видны только в офлайн-режиме и
+никогда не синхронизируются с аккаунтом. Чтобы игру можно было создать и сыграть без связи, приложение
+заранее, пока ещё онлайн, подгружает словари включённых игроком вариантов и (после установки)
+запускается из прекешированного шелла даже без сети. Переключение **в** офлайн сначала проверяет, что
+словари включённых вариантов есть на устройстве — если каких-то не хватает, оно их подгружает и недолго
+ждёт, а если подготовить их не удаётся, остаётся онлайн с короткой заметкой *нужен интернет* (загрузка
+продолжается в фоне, так что следующее переключение мгновенно). Режим привязан к устройству и
+сохраняется между запусками.
+
+В офлайне «с друзьями» в Новой игре запускает **локальную игру по очереди (hotseat)** на 2–4 человек
+за одним устройством. Сначала задаётся **пароль ведущего** — 4-значный PIN на клавиатуре в стиле
+экрана блокировки; пока он не задан, строки игроков заблокированы. Затем приложение спрашивает,
+играете ли вы сами — если да, вы занимаете первое место под именем из профиля. Вы называете каждого
+игрока (от 2 до 4; строки можно добавлять и удалять, удаление спрашивает пароль ведущего) и можете
+дать любому месту **свой необязательный PIN**. Во время игры доска видна всегда, но место с PIN
+вместо стойки показывает кнопку **«Разблокировать»**, пока владелец не введёт PIN, — так устройство
+передаётся из рук в руки, и только защищённое место прячет свои буквы; на каждом ходу замок
+возвращается. **Ведущий** (кнопка ведущего в игре) может по паролю ведущего **пропустить** ход
+текущего игрока, **исключить** игрока или **завершить игру досрочно** — досрочное завершение стирает
+партию без победителей и проигравших. Подсказки и чат в игре по очереди отключены. Нормально
+завершённая партия сохраняется в офлайн-лобби как любая другая; удаление любой игры по очереди —
+идущей или завершённой — из лобби спрашивает пароль ведущего, чтобы никто не стёр партию сразу после
+своего хода.
+
+Приложение также **само включает офлайн-режим**, когда не может достучаться до сети. При холодном
+запуске без связи оно переходит в офлайн на текущую сессию; когда устройство онлайн, но шлюз молчит
+несколько секунд, оно сперва спрашивает — *Нет связи. Включить офлайн-режим?*, с выбором **Включить**
+(уйти в офлайн) или **Ждать сеть** (продолжить попытки онлайн). Пока приложение открыто, потеря сети —
+режим полёта — переключает в офлайн автоматически, а её восстановление само возвращает онлайн.
+Самостоятельно включённый офлайн временный: он возвращается в онлайн, как только сеть появилась, и
+следующий запуск проверяет заново. **Осознанный** офлайн — тумблер в Настройках или **Включить** в том
+диалоге — это выбор игрока: он сохраняется и никогда не отменяется автоматически.
+
 ### Социальное: друзья, блок, чат, nudge
 Подружиться можно двумя способами: погасить **одноразовый код**, который выпускает
 другой игрок (шесть цифр, действует двенадцать часов), либо отправить **заявку

docs/TESTING.md

@@ -20,7 +20,18 @@ tests or touching CI.
   derivation and the GCG share/copy/download choice, plus Playwright specs against the
   mock for the friends screen (code issue/redeem, accept a request), the lobby
   invitations section, the stats screen, profile editing, and the export chooser's
-  finished-only visibility + its signed-URL download flow (route-intercepted).
+  finished-only visibility + its signed-URL download flow (route-intercepted). The
+  **offline mode** spec (`e2e/offline.spec.ts`) plays a full device-local `vs_ai` game
+  end-to-end: it forces the installed-PWA display mode, enters offline through the
+  Settings toggle (whose readiness check fetches the enabled variants' dawgs), then creates
+  and plays a local game with a **pinned bag seed** (`window.__mock.setLocalSeed`, so the
+  rack is deterministic and the human can tap out a precomputed opening), asserting the
+  robot's real reply and the IndexedDB replay after a reload. A local game needs a real
+  dictionary, so the mock's `fetchDict` serves the per-variant dawgs from the preview
+  build's `/e2edict/`, copied in by `scripts/e2e-dict.mjs` from `E2E_DICT_DIR` — the `ui`
+  CI job fetches the `scrabble-dictionary` release like the Go jobs; locally it defaults to
+  the sibling `scrabble-solver/dawg`. These dawgs are never committed and never enter the
+  production build.
 - **Render sidecar** — `renderer/` (Node + skia-canvas executing the shared
   `ui/src/lib/gameimage.ts`) carries a `node --test` smoke: the committed fixture (a
   real self-played 35-move game) must rasterize to a plausible PNG

gateway/README.md

@@ -8,6 +8,10 @@ backend over REST/JSON, and bridges the backend's gRPC push stream to each
 client's in-app live channel. It **embeds the static UI build** (`go:embed`, baked
 in by the gateway image's node stage) and serves a **landing page** at `/` and the game
 **SPA** at `/app/` (web), `/telegram/` (the Telegram Mini App) and `/vk/` (the VK Mini App) — the single-origin model.
+The web SPA is an installable **PWA**: it serves `manifest.webmanifest` (unhashed from `ui/public/`,
+with the `.webmanifest` MIME type registered in-process — the distroless image has no
+`/etc/mime.types`) and the app-shell `sw.js` (built from `ui/src/sw.ts` by vite-plugin-pwa, which
+precaches the shell + assets so an installed PWA cold-launches offline).
 Hash-named `/assets/*` are served `immutable`; the HTML shells are `no-cache`. It can also serve the
 backend's admin console at `/_gm` behind HTTP Basic-Auth for a local non-caddy run;
 in the deployed contour the front caddy owns `/_gm` (see

gateway/internal/backendclient/api.go

@@ -42,6 +42,15 @@ type ProfileResp struct {
 	Email          string `json:"email"`
 	TelegramLinked bool   `json:"telegram_linked"`
 	VkLinked       bool   `json:"vk_linked"`
+	// DictVersions is the current dictionary version per game variant, forwarded verbatim
+	// into the Profile payload so an offline-capable client preloads the matching dawg.
+	DictVersions []DictVersion `json:"dict_versions,omitempty"`
+}
+
+// DictVersion pairs a game variant's stable label with its current dictionary version.
+type DictVersion struct {
+	Variant string `json:"variant"`
+	Version string `json:"version"`
 }
 
 // BannerResp is the advertising-banner block of an eligible viewer's profile: the
@@ -172,13 +181,14 @@ type AlphabetEntryJSON struct {
 // StateResp is a player's view of a game. Rack carries wire alphabet indices;
 // Alphabet is present only when the request asked for it.
 type StateResp struct {
-	Game           GameResp            `json:"game"`
+	Game                  GameResp            `json:"game"`
-	Seat           int                 `json:"seat"`
+	Seat                  int                 `json:"seat"`
-	Rack           []int               `json:"rack"`
+	Rack                  []int               `json:"rack"`
-	BagLen         int                 `json:"bag_len"`
+	BagLen                int                 `json:"bag_len"`
-	HintsRemaining int                 `json:"hints_remaining"`
+	HintsRemaining        int                 `json:"hints_remaining"`
-	WalletBalance  int                 `json:"wallet_balance"`
+	WalletBalance         int                 `json:"wallet_balance"`
-	Alphabet       []AlphabetEntryJSON `json:"alphabet,omitempty"`
+	HintUnlockLeftSeconds int                 `json:"hint_unlock_left_seconds"`
+	Alphabet              []AlphabetEntryJSON `json:"alphabet,omitempty"`
 }
 
 // MatchResp reports an auto-match outcome.
@@ -289,10 +299,11 @@ func (c *Client) GuestAuth(ctx context.Context, browserTz string) (SessionResp,
 
 // EmailRequest asks the backend to mail a login code, provisioning the account on
 // first contact; browserTz (the client's detected "±HH:MM" UTC offset) seeds the new
-// account's time zone, since the email account is created here, not at login.
+// account's time zone, since the email account is created here, not at login. pwa marks a
-func (c *Client) EmailRequest(ctx context.Context, email, browserTz, language string) error {
+// request from an installed PWA, so the backend omits the one-tap confirm link from the email.
+func (c *Client) EmailRequest(ctx context.Context, email, browserTz, language string, pwa bool) error {
 	return c.do(ctx, http.MethodPost, "/api/v1/internal/sessions/email/request", "", "",
-		map[string]string{"email": email, "browser_tz": browserTz, "language": language}, nil)
+		map[string]any{"email": email, "browser_tz": browserTz, "language": language, "pwa": pwa}, nil)
 }
 
 // EmailLogin verifies a login code and mints a session.

gateway/internal/connectsrv/metrics.go

@@ -46,7 +46,13 @@ func newServerMetrics(meter metric.Meter) *serverMetrics {
 	}
 	h, err := meter.Float64Histogram("edge_request_duration",
 		metric.WithUnit("s"),
-		metric.WithDescription("Seconds to serve one Connect Execute call, by message type and result."))
+		metric.WithDescription("Seconds to serve one Connect Execute call, by message type and result."),
+		// Explicit second-scale buckets. The durations are recorded in seconds, so the SDK's
+		// default millisecond-calibrated boundaries (first boundary 5) would bin every sub-5s
+		// request into one bucket — making histogram_quantile(0.99) interpolate to ~4.95s
+		// regardless of the real latency, which flapped the >1s edge-latency alert. These
+		// boundaries straddle the 1s SLO so the p99 reflects real (mostly sub-second) latency.
+		metric.WithExplicitBucketBoundaries(0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2.5, 5, 10))
 	if err != nil {
 		h, _ = noop.NewMeterProvider().Meter(meterName).Float64Histogram("edge_request_duration")
 	}

gateway/internal/connectsrv/metrics_test.go

@@ -29,6 +29,7 @@ func TestEdgeMetric(t *testing.T) {
 
 	type key struct{ messageType, result string }
 	counts := map[key]uint64{}
+	var bounds []float64
 	for _, sm := range rm.ScopeMetrics {
 		for _, md := range sm.Metrics {
 			if md.Name != "edge_request_duration" {
@@ -42,6 +43,7 @@ func TestEdgeMetric(t *testing.T) {
 				mt, _ := dp.Attributes.Value(attribute.Key("message_type"))
 				res, _ := dp.Attributes.Value(attribute.Key("result"))
 				counts[key{mt.AsString(), res.AsString()}] += dp.Count
+				bounds = dp.Bounds
 			}
 		}
 	}
@@ -51,6 +53,19 @@ func TestEdgeMetric(t *testing.T) {
 	if got := counts[key{"auth.guest", "domain"}]; got != 1 {
 		t.Errorf("edge auth.guest/domain = %d, want 1", got)
 	}
+	// The buckets must be second-scaled. The default (millisecond-calibrated) boundaries have no
+	// boundary between 0 and 5, so every sub-5s request bins into one bucket and p99 interpolates
+	// to ~4.95s, flapping the >1s alert. Require at least one sub-second boundary.
+	subSecond := false
+	for _, b := range bounds {
+		if b > 0 && b < 1 {
+			subSecond = true
+			break
+		}
+	}
+	if !subSecond {
+		t.Errorf("edge_request_duration bounds = %v, want sub-second boundaries (seconds-scaled)", bounds)
+	}
 }
 
 // TestRateLimitedMetric records limiter rejections through a manual reader and

gateway/internal/transcode/encode.go

@@ -95,6 +95,7 @@ func encodeProfile(p backendclient.ProfileResp) []byte {
 		banner = encodeBanner(b, *p.Banner)
 	}
 	prefs := buildStringVector(b, p.VariantPreferences, fb.ProfileStartVariantPreferencesVector)
+	dictVersions := encodeDictVersions(b, p.DictVersions)
 	fb.ProfileStart(b)
 	fb.ProfileAddUserId(b, uid)
 	fb.ProfileAddDisplayName(b, name)
@@ -111,6 +112,9 @@ func encodeProfile(p backendclient.ProfileResp) []byte {
 	fb.ProfileAddEmail(b, email)
 	fb.ProfileAddTelegramLinked(b, p.TelegramLinked)
 	fb.ProfileAddVkLinked(b, p.VkLinked)
+	if dictVersions != 0 {
+		fb.ProfileAddDictVersions(b, dictVersions)
+	}
 	if p.Banner != nil {
 		fb.ProfileAddBanner(b, banner)
 	}
@@ -118,6 +122,31 @@ func encodeProfile(p backendclient.ProfileResp) []byte {
 	return b.FinishedBytes()
 }
 
+// encodeDictVersions builds the Profile's dict_versions vector — one DictVersion table per
+// variant/version pair — and returns its offset, or 0 when there are none (the field is then
+// omitted). Every child table and its strings are created before the vector is opened, per the
+// FlatBuffers rule against nesting a table under one still being built; the caller invokes it
+// before ProfileStart for the same reason.
+func encodeDictVersions(b *flatbuffers.Builder, dvs []backendclient.DictVersion) flatbuffers.UOffsetT {
+	if len(dvs) == 0 {
+		return 0
+	}
+	offsets := make([]flatbuffers.UOffsetT, len(dvs))
+	for i, dv := range dvs {
+		variant := b.CreateString(dv.Variant)
+		version := b.CreateString(dv.Version)
+		fb.DictVersionStart(b)
+		fb.DictVersionAddVariant(b, variant)
+		fb.DictVersionAddVersion(b, version)
+		offsets[i] = fb.DictVersionEnd(b)
+	}
+	fb.ProfileStartDictVersionsVector(b, len(offsets))
+	for i := len(offsets) - 1; i >= 0; i-- {
+		b.PrependUOffsetT(offsets[i])
+	}
+	return b.EndVector(len(offsets))
+}
+
 // optString creates a FlatBuffers string for a non-empty value, or 0 to omit the
 // optional field (the client then reads it as absent).
 func optString(b *flatbuffers.Builder, s string) flatbuffers.UOffsetT {
@@ -270,13 +299,14 @@ func toWireState(s backendclient.StateResp) wire.StateView {
 		alphabet[i] = wire.AlphabetEntry{Index: e.Index, Letter: e.Letter, Value: e.Value}
 	}
 	return wire.StateView{
-		Game:           toWireGame(s.Game),
+		Game:                  toWireGame(s.Game),
-		Seat:           s.Seat,
+		Seat:                  s.Seat,
-		Rack:           s.Rack,
+		Rack:                  s.Rack,
-		BagLen:         s.BagLen,
+		BagLen:                s.BagLen,
-		HintsRemaining: s.HintsRemaining,
+		HintsRemaining:        s.HintsRemaining,
-		WalletBalance:  s.WalletBalance,
+		WalletBalance:         s.WalletBalance,
-		Alphabet:       alphabet,
+		HintUnlockLeftSeconds: s.HintUnlockLeftSeconds,
+		Alphabet:              alphabet,
 	}
 }
 

gateway/internal/transcode/transcode.go

@@ -253,7 +253,7 @@ func authGuestHandler(backend *backendclient.Client) Handler {
 func authEmailRequestHandler(backend *backendclient.Client) Handler {
 	return func(ctx context.Context, req Request) ([]byte, error) {
 		in := fb.GetRootAsEmailRequestRequest(req.Payload, 0)
-		if err := backend.EmailRequest(ctx, string(in.Email()), string(in.BrowserTz()), string(in.Language())); err != nil {
+		if err := backend.EmailRequest(ctx, string(in.Email()), string(in.BrowserTz()), string(in.Language()), in.Pwa()); err != nil {
 			return nil, err
 		}
 		return encodeAck(true), nil

gateway/internal/transcode/transcode_test.go

@@ -59,7 +59,7 @@ func TestGameStateRoundTripForwardsUserID(t *testing.T) {
 		if r.URL.Path != "/api/v1/user/games/g-1/state" {
 			t.Errorf("unexpected path %q", r.URL.Path)
 		}
-		_, _ = w.Write([]byte(`{"game":{"id":"g-1","variant":"scrabble_en","status":"active","players":2,"to_move":1,"seats":[{"seat":0,"account_id":"u-7","score":5}]},"seat":0,"rack":[0,1],"bag_len":80,"hints_remaining":4,"wallet_balance":3}`))
+		_, _ = w.Write([]byte(`{"game":{"id":"g-1","variant":"scrabble_en","status":"active","players":2,"to_move":1,"seats":[{"seat":0,"account_id":"u-7","score":5}]},"seat":0,"rack":[0,1],"bag_len":80,"hints_remaining":4,"wallet_balance":3,"hint_unlock_left_seconds":1200}`))
 	})
 	defer cleanup()
 
@@ -77,8 +77,8 @@ func TestGameStateRoundTripForwardsUserID(t *testing.T) {
 		t.Fatalf("handler: %v", err)
 	}
 	st := fb.GetRootAsStateView(payload, 0)
-	if st.BagLen() != 80 || st.RackLength() != 2 || st.HintsRemaining() != 4 || st.WalletBalance() != 3 {
+	if st.BagLen() != 80 || st.RackLength() != 2 || st.HintsRemaining() != 4 || st.WalletBalance() != 3 || st.HintUnlockLeftSeconds() != 1200 {
-		t.Fatalf("state decoded wrong: bag=%d rack=%d hints=%d wallet=%d", st.BagLen(), st.RackLength(), st.HintsRemaining(), st.WalletBalance())
+		t.Fatalf("state decoded wrong: bag=%d rack=%d hints=%d wallet=%d unlockLeft=%d", st.BagLen(), st.RackLength(), st.HintsRemaining(), st.WalletBalance(), st.HintUnlockLeftSeconds())
 	}
 	game := st.Game(nil)
 	if game == nil || string(game.Id()) != "g-1" || string(game.Variant()) != "scrabble_en" || game.ToMove() != 1 {

gateway/internal/webui/webui.go

@@ -17,6 +17,7 @@ package webui
 import (
 	"embed"
 	"io/fs"
+	"mime"
 	"net/http"
 	"path"
 	"strings"
@@ -35,13 +36,25 @@ func distFS() fs.FS {
 	return sub
 }
 
-// Handler serves the embedded UI. An existing file is served directly (hash-named assets get
+// init registers the MIME type for .webmanifest, which Go's built-in table lacks and the
-// an immutable cache); every other path falls back to indexName (the SPA shell) so a
+// distroless runtime image has no /etc/mime.types to supply. Without it the PWA Web App Manifest
-// client-side deep link still loads. When stripPrefix is non-empty it is removed from the
+// served under /app/ would be content-sniffed to text/plain, which some browsers reject.
-// request path before lookup, so the same build serves under a sub-path (e.g. "/app/" or
+func init() {
-// "/telegram/").
+	_ = mime.AddExtensionType(".webmanifest", "application/manifest+json")
+}
+
+// Handler serves the compile-time embedded UI build over the public edge — the game SPA under
+// /app/, /telegram/ and /vk/. It delegates to handlerFor over the embedded dist/.
 func Handler(stripPrefix, indexName string) http.Handler {
-	content := distFS()
+	return handlerFor(distFS(), stripPrefix, indexName)
+}
+
+// handlerFor serves content as the UI: an existing file is served directly (hash-named assets get
+// an immutable cache); every other path falls back to indexName (the SPA shell) so a client-side
+// deep link still loads. When stripPrefix is non-empty it is removed from the request path before
+// lookup, so the same build serves under a sub-path (e.g. "/app/" or "/telegram/"). Split from
+// Handler so it can be exercised over an in-memory fs.FS in tests.
+func handlerFor(content fs.FS, stripPrefix, indexName string) http.Handler {
 	files := http.FileServer(http.FS(content))
 	h := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		name := strings.TrimPrefix(path.Clean("/"+r.URL.Path), "/")
@@ -58,6 +71,11 @@ func Handler(stripPrefix, indexName string) http.Handler {
 		// app (notably a relaunched Telegram Mini App) is a cache hit, not a re-download.
 		if strings.HasPrefix(name, "assets/") {
 			w.Header().Set("Cache-Control", "public, max-age=31536000, immutable")
+		} else if name == "sw.js" {
+			// The service worker must be revalidated on every load so a new deploy's worker (and its
+			// fresh precache manifest) is picked up promptly; a cached sw.js would strand clients on
+			// the old build. The worker's network-first navigation then serves the fresh shell online.
+			w.Header().Set("Cache-Control", "no-cache")
 		}
 		files.ServeHTTP(w, r)
 	})

gateway/internal/webui/webui_test.go

@@ -6,6 +6,7 @@ import (
 	"net/http/httptest"
 	"strings"
 	"testing"
+	"testing/fstest"
 )
 
 // get drives the handler with a GET for the given path and returns the response.
@@ -55,3 +56,60 @@ func TestAppMountServesShellStripsPrefixAndCachesAssets(t *testing.T) {
 		}
 	}
 }
+
+// testFS mirrors what Vite emits into dist/: the SPA shell, the PWA manifest + service worker at
+// the root (copied from ui/public), and a hash-named asset. The compile-time embedded dist/ holds
+// only a placeholder shell, so the manifest/sw.js serving is exercised over this in-memory FS.
+func testFS() fstest.MapFS {
+	return fstest.MapFS{
+		"index.html":           {Data: []byte("<!doctype html><title>shell</title>")},
+		"manifest.webmanifest": {Data: []byte(`{"name":"Эрудит"}`)},
+		"sw.js":                {Data: []byte("self.addEventListener('fetch', () => {});")},
+		"assets/app-abc123.js": {Data: []byte("export const x = 1;")},
+	}
+}
+
+// TestHandlerServesManifestWithManifestType: the PWA manifest is served with the manifest MIME
+// type (registered in init, since the distroless image has no /etc/mime.types), not sniffed to
+// text/plain, which some browsers reject.
+func TestHandlerServesManifestWithManifestType(t *testing.T) {
+	h := handlerFor(testFS(), "/app/", "index.html")
+	resp := get(t, h, "/app/manifest.webmanifest")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("status = %d, want 200", resp.StatusCode)
+	}
+	if ct := resp.Header.Get("Content-Type"); !strings.HasPrefix(ct, "application/manifest+json") {
+		t.Errorf("Content-Type = %q, want application/manifest+json", ct)
+	}
+}
+
+// TestHandlerServesServiceWorkerAsJavaScript: sw.js is served as JavaScript from the root, so its
+// registration (scope /app/) succeeds.
+func TestHandlerServesServiceWorkerAsJavaScript(t *testing.T) {
+	h := handlerFor(testFS(), "/app/", "index.html")
+	resp := get(t, h, "/app/sw.js")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("status = %d, want 200", resp.StatusCode)
+	}
+	if ct := resp.Header.Get("Content-Type"); !strings.HasPrefix(ct, "text/javascript") {
+		t.Errorf("Content-Type = %q, want text/javascript", ct)
+	}
+	// Revalidated on every load so a new deploy's worker (and its fresh precache) is picked up.
+	if cc := resp.Header.Get("Cache-Control"); cc != "no-cache" {
+		t.Errorf("sw.js Cache-Control = %q, want no-cache", cc)
+	}
+}
+
+// TestHandlerFallsBackToShellForUnknownManifestPath guards the trap: a manifest/sw path NOT emitted
+// into dist/ falls back to the SPA shell as text/html, on which SW registration would fail. The two
+// tests above pin that the real files are served instead of the shell.
+func TestHandlerFallsBackToShellForUnknownManifestPath(t *testing.T) {
+	h := handlerFor(testFS(), "/app/", "index.html")
+	resp := get(t, h, "/app/not-emitted.webmanifest")
+	if resp.StatusCode != http.StatusOK {
+		t.Fatalf("status = %d, want 200", resp.StatusCode)
+	}
+	if ct := resp.Header.Get("Content-Type"); !strings.HasPrefix(ct, "text/html") {
+		t.Errorf("Content-Type = %q, want text/html (SPA shell fallback)", ct)
+	}
+}

pkg/fbs/scrabble.fbs

@@ -138,6 +138,11 @@ table EmailRequestRequest {
   email:string;
   browser_tz:string;
   language:string;
+  // Set when the request originates from an installed PWA (standalone display mode): the
+  // backend then omits the one-tap confirm link from the login email so the code is typed in
+  // the same window, avoiding a link that opens in a separate browser (a different storage
+  // context) where the minted session could not reach the PWA.
+  pwa:bool;
 }
 
 // EmailLoginRequest logs in to the account owning email (provisioned at the
@@ -218,6 +223,13 @@ table BannerInfo {
 // suppresses out-of-app platform push, leaving only the in-app live stream. banner
 // carries the advertising-banner block for an eligible viewer, absent otherwise
 // (all added trailing — backward-compatible).
+// DictVersion is one variant's current dictionary version, carried on the profile so an offline
+// client learns it from an existing cold-start request (no extra call for a rarely-used feature).
+table DictVersion {
+  variant:string;
+  version:string;
+}
+
 table Profile {
   user_id:string;
   display_name:string;
@@ -240,6 +252,10 @@ table Profile {
   email:string;
   telegram_linked:bool;
   vk_linked:bool;
+  // dict_versions carries each variant's current dictionary version so an offline client can
+  // preload the right dictionary and pin a new local game without a separate request (added
+  // trailing — backward-compatible).
+  dict_versions:[DictVersion];
 }
 
 // BlockStatus reports the caller's current manual block. The UI fetches it after any operation
@@ -300,6 +316,13 @@ table StateView {
   // the wallet is a single global figure the client keeps live across games (added trailing —
   // backward-compatible).
   wallet_balance:int;
+  // hint_unlock_left_seconds is, for a vs_ai game, how many seconds until the idle hint unlocks
+  // (the robot's last move plus the idle window, computed from the SERVER clock online / the device
+  // clock offline, capped at the window and floored at 0); 0 for a human's first move (no robot move
+  // yet) or a non-vs_ai game. The client anchors a MONOTONIC countdown (performance.now()) to it, so a
+  // client clock change cannot skew it — see lib/hints. Seconds granularity is enough; sent trailing
+  // (additive, backward-compatible).
+  hint_unlock_left_seconds:int;
 }
 
 // GameActionRequest carries just a game id (pass / resign / hint / history).

pkg/fbs/scrabblefb/DictVersion.go

@@ -0,0 +1,71 @@
+// Code generated by the FlatBuffers compiler. DO NOT EDIT.
+
+package scrabblefb
+
+import (
+	flatbuffers "github.com/google/flatbuffers/go"
+)
+
+type DictVersion struct {
+	_tab flatbuffers.Table
+}
+
+func GetRootAsDictVersion(buf []byte, offset flatbuffers.UOffsetT) *DictVersion {
+	n := flatbuffers.GetUOffsetT(buf[offset:])
+	x := &DictVersion{}
+	x.Init(buf, n+offset)
+	return x
+}
+
+func FinishDictVersionBuffer(builder *flatbuffers.Builder, offset flatbuffers.UOffsetT) {
+	builder.Finish(offset)
+}
+
+func GetSizePrefixedRootAsDictVersion(buf []byte, offset flatbuffers.UOffsetT) *DictVersion {
+	n := flatbuffers.GetUOffsetT(buf[offset+flatbuffers.SizeUint32:])
+	x := &DictVersion{}
+	x.Init(buf, n+offset+flatbuffers.SizeUint32)
+	return x
+}
+
+func FinishSizePrefixedDictVersionBuffer(builder *flatbuffers.Builder, offset flatbuffers.UOffsetT) {
+	builder.FinishSizePrefixed(offset)
+}
+
+func (rcv *DictVersion) Init(buf []byte, i flatbuffers.UOffsetT) {
+	rcv._tab.Bytes = buf
+	rcv._tab.Pos = i
+}
+
+func (rcv *DictVersion) Table() flatbuffers.Table {
+	return rcv._tab
+}
+
+func (rcv *DictVersion) Variant() []byte {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(4))
+	if o != 0 {
+		return rcv._tab.ByteVector(o + rcv._tab.Pos)
+	}
+	return nil
+}
+
+func (rcv *DictVersion) Version() []byte {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(6))
+	if o != 0 {
+		return rcv._tab.ByteVector(o + rcv._tab.Pos)
+	}
+	return nil
+}
+
+func DictVersionStart(builder *flatbuffers.Builder) {
+	builder.StartObject(2)
+}
+func DictVersionAddVariant(builder *flatbuffers.Builder, variant flatbuffers.UOffsetT) {
+	builder.PrependUOffsetTSlot(0, flatbuffers.UOffsetT(variant), 0)
+}
+func DictVersionAddVersion(builder *flatbuffers.Builder, version flatbuffers.UOffsetT) {
+	builder.PrependUOffsetTSlot(1, flatbuffers.UOffsetT(version), 0)
+}
+func DictVersionEnd(builder *flatbuffers.Builder) flatbuffers.UOffsetT {
+	return builder.EndObject()
+}

pkg/fbs/scrabblefb/EmailRequestRequest.go

@@ -65,8 +65,20 @@ func (rcv *EmailRequestRequest) Language() []byte {
 	return nil
 }
 
+func (rcv *EmailRequestRequest) Pwa() bool {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(10))
+	if o != 0 {
+		return rcv._tab.GetBool(o + rcv._tab.Pos)
+	}
+	return false
+}
+
+func (rcv *EmailRequestRequest) MutatePwa(n bool) bool {
+	return rcv._tab.MutateBoolSlot(10, n)
+}
+
 func EmailRequestRequestStart(builder *flatbuffers.Builder) {
-	builder.StartObject(3)
+	builder.StartObject(4)
 }
 func EmailRequestRequestAddEmail(builder *flatbuffers.Builder, email flatbuffers.UOffsetT) {
 	builder.PrependUOffsetTSlot(0, flatbuffers.UOffsetT(email), 0)
@@ -77,6 +89,9 @@ func EmailRequestRequestAddBrowserTz(builder *flatbuffers.Builder, browserTz fla
 func EmailRequestRequestAddLanguage(builder *flatbuffers.Builder, language flatbuffers.UOffsetT) {
 	builder.PrependUOffsetTSlot(2, flatbuffers.UOffsetT(language), 0)
 }
+func EmailRequestRequestAddPwa(builder *flatbuffers.Builder, pwa bool) {
+	builder.PrependBoolSlot(3, pwa, false)
+}
 func EmailRequestRequestEnd(builder *flatbuffers.Builder) flatbuffers.UOffsetT {
 	return builder.EndObject()
 }

pkg/fbs/scrabblefb/Profile.go

@@ -211,8 +211,28 @@ func (rcv *Profile) MutateVkLinked(n bool) bool {
 	return rcv._tab.MutateBoolSlot(34, n)
 }
 
+func (rcv *Profile) DictVersions(obj *DictVersion, j int) bool {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(36))
+	if o != 0 {
+		x := rcv._tab.Vector(o)
+		x += flatbuffers.UOffsetT(j) * 4
+		x = rcv._tab.Indirect(x)
+		obj.Init(rcv._tab.Bytes, x)
+		return true
+	}
+	return false
+}
+
+func (rcv *Profile) DictVersionsLength() int {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(36))
+	if o != 0 {
+		return rcv._tab.VectorLen(o)
+	}
+	return 0
+}
+
 func ProfileStart(builder *flatbuffers.Builder) {
-	builder.StartObject(16)
+	builder.StartObject(17)
 }
 func ProfileAddUserId(builder *flatbuffers.Builder, userId flatbuffers.UOffsetT) {
 	builder.PrependUOffsetTSlot(0, flatbuffers.UOffsetT(userId), 0)
@@ -265,6 +285,12 @@ func ProfileAddTelegramLinked(builder *flatbuffers.Builder, telegramLinked bool)
 func ProfileAddVkLinked(builder *flatbuffers.Builder, vkLinked bool) {
 	builder.PrependBoolSlot(15, vkLinked, false)
 }
+func ProfileAddDictVersions(builder *flatbuffers.Builder, dictVersions flatbuffers.UOffsetT) {
+	builder.PrependUOffsetTSlot(16, flatbuffers.UOffsetT(dictVersions), 0)
+}
+func ProfileStartDictVersionsVector(builder *flatbuffers.Builder, numElems int) flatbuffers.UOffsetT {
+	return builder.StartVector(4, numElems, 4)
+}
 func ProfileEnd(builder *flatbuffers.Builder) flatbuffers.UOffsetT {
 	return builder.EndObject()
 }

pkg/fbs/scrabblefb/StateView.go

@@ -156,8 +156,20 @@ func (rcv *StateView) MutateWalletBalance(n int32) bool {
 	return rcv._tab.MutateInt32Slot(16, n)
 }
 
+func (rcv *StateView) HintUnlockLeftSeconds() int32 {
+	o := flatbuffers.UOffsetT(rcv._tab.Offset(18))
+	if o != 0 {
+		return rcv._tab.GetInt32(o + rcv._tab.Pos)
+	}
+	return 0
+}
+
+func (rcv *StateView) MutateHintUnlockLeftSeconds(n int32) bool {
+	return rcv._tab.MutateInt32Slot(18, n)
+}
+
 func StateViewStart(builder *flatbuffers.Builder) {
-	builder.StartObject(7)
+	builder.StartObject(8)
 }
 func StateViewAddGame(builder *flatbuffers.Builder, game flatbuffers.UOffsetT) {
 	builder.PrependUOffsetTSlot(0, flatbuffers.UOffsetT(game), 0)
@@ -186,6 +198,9 @@ func StateViewStartAlphabetVector(builder *flatbuffers.Builder, numElems int) fl
 func StateViewAddWalletBalance(builder *flatbuffers.Builder, walletBalance int32) {
 	builder.PrependInt32Slot(6, walletBalance, 0)
 }
+func StateViewAddHintUnlockLeftSeconds(builder *flatbuffers.Builder, hintUnlockLeftSeconds int32) {
+	builder.PrependInt32Slot(7, hintUnlockLeftSeconds, 0)
+}
 func StateViewEnd(builder *flatbuffers.Builder) flatbuffers.UOffsetT {
 	return builder.EndObject()
 }

pkg/wire/build.go

@@ -87,13 +87,14 @@ type AlphabetEntry struct {
 // (wire alphabet indices), bag size and hint budget. Alphabet is set only when the
 // recipient may not have cached the variant's display table yet.
 type StateView struct {
-	Game           GameView
+	Game                  GameView
-	Seat           int
+	Seat                  int
-	Rack           []int
+	Rack                  []int
-	BagLen         int
+	BagLen                int
-	HintsRemaining int
+	HintsRemaining        int
-	WalletBalance  int
+	WalletBalance         int
-	Alphabet       []AlphabetEntry
+	HintUnlockLeftSeconds int
+	Alphabet              []AlphabetEntry
 }
 
 // AccountRef is a referenced account with its display name resolved.
@@ -256,6 +257,7 @@ func BuildStateView(b *flatbuffers.Builder, s StateView) flatbuffers.UOffsetT {
 	fb.StateViewAddBagLen(b, int32(s.BagLen))
 	fb.StateViewAddHintsRemaining(b, int32(s.HintsRemaining))
 	fb.StateViewAddWalletBalance(b, int32(s.WalletBalance))
+	fb.StateViewAddHintUnlockLeftSeconds(b, int32(s.HintUnlockLeftSeconds))
 	if hasAlphabet {
 		fb.StateViewAddAlphabet(b, alphabet)
 	}

ui/e2e/hotseat.spec.ts

@@ -0,0 +1,126 @@
+import { test, expect, type Page } from './fixtures';
+
+// Offline pass-and-play (hotseat) is offered only in offline mode, which is gated to an installed
+// standalone PWA with a confirmed email. The mock account has an email; force standalone so the
+// Settings offline toggle shows.
+async function forceStandalone(page: Page): Promise<void> {
+  await page.addInitScript(() => {
+    const orig = window.matchMedia.bind(window);
+    window.matchMedia = (q: string) =>
+      (q.includes('display-mode: standalone')
+        ? { matches: true, media: q, onchange: null, addEventListener() {}, removeEventListener() {}, addListener() {}, removeListener() {}, dispatchEvent: () => false }
+        : orig(q)) as MediaQueryList;
+  });
+}
+
+async function enterLobby(page: Page): Promise<void> {
+  await page.getByRole('button', { name: /guest|гост/i }).first().click();
+  await expect(page.locator('button.tab').nth(2)).toBeVisible();
+}
+
+async function goOffline(page: Page): Promise<void> {
+  await page.locator('button.tab').nth(2).click(); // Settings
+  await page.getByRole('button', { name: /^(Offline|Оффлайн)$/ }).click();
+  await expect(page.locator('header.nav.offline')).toBeVisible({ timeout: 15000 });
+  await page.getByRole('button', { name: /Back|Назад/i }).click();
+  await expect(page.locator('button.tab').nth(2)).toBeVisible();
+}
+
+// typePin clicks the on-screen keypad digits (the pad has no OK button — the 4th digit is the action).
+// It first waits for the dots to be empty, so a call made right after a previous entry does not lose
+// digits during the 250 ms verdict pause (the 4th digit → pause → clear/advance).
+async function typePin(page: Page, digits: string): Promise<void> {
+  await expect(page.locator('.pad .dot.on')).toHaveCount(0);
+  for (const d of digits) await page.locator('.pad .key', { hasText: d }).click();
+}
+
+test.describe('offline hotseat (pass-and-play)', () => {
+  test('create with a locked seat, unlock, host-skip, terminate from the lobby', async ({ page }) => {
+    await forceStandalone(page);
+    await page.goto('/');
+    await enterLobby(page);
+    await goOffline(page);
+
+    // A known seed: the bag deals a full rack deterministically, AND the seeded seating shuffle keeps
+    // the roster order (Ann first) so the locked-seat assertions below are stable. (Seat order is
+    // randomised at start; the shuffle is seed-driven — seed '1' would seat Bob first, '2' Ann first.)
+    await page.evaluate(() => (window as unknown as { __mock: { setLocalSeed(s: string): void } }).__mock.setLocalSeed('2'));
+
+    // New game -> the offline mode selector now offers "with friends" (hotseat).
+    await page.locator('button.tab').nth(0).click();
+    await page.getByRole('button', { name: /With friends|друзьями/i }).click();
+
+    // The player rows are disabled until the mandatory host (master) PIN is set.
+    await expect(page.locator('.pname').first()).toBeDisabled();
+
+    // Set the host PIN (enter + confirm), then decline taking a seat.
+    await page.locator('.hostpin .plink').click();
+    await typePin(page, '9999');
+    await typePin(page, '9999');
+    await page.getByRole('button', { name: /^(No|Нет)$/ }).click();
+
+    // Pick the English variant (the plaques mirror Quick Match; "Scrabble" is the Latin English name).
+    await page.locator('.variant', { hasText: 'Scrabble' }).click();
+
+    // Two players: Ann (PIN-locked) and Bob (open).
+    await page.locator('.pname').nth(0).fill('Ann');
+    await page.locator('.pname').nth(1).fill('Bob');
+
+    // Row-delete: a 3rd player's kebab asks the host PIN, which ARMS a ❌ (not a silent delete);
+    // tapping the ❌ removes the row.
+    await page.getByRole('button', { name: /Add player|Добавить/i }).click();
+    await expect(page.locator('.prow')).toHaveCount(3);
+    await page.locator('.prow').nth(2).locator('.pkebab').click();
+    await typePin(page, '9999');
+    const rowDel = page.locator('.prow').nth(2).locator('.prow-del');
+    await expect(rowDel).toBeVisible();
+    await rowDel.click();
+    await expect(page.locator('.prow')).toHaveCount(2);
+
+    // Lock Ann's seat with a PIN.
+    await page.locator('.prow').nth(0).locator('.plink').click();
+    await typePin(page, '1234');
+    await typePin(page, '1234');
+
+    await page.locator('button.invite').click();
+    await expect(page.locator('[data-cell]').first()).toBeVisible();
+
+    // Ann is to move and PIN-locked: the board is visible but her rack is withheld behind Unlock.
+    await expect(page.locator('.unlock')).toBeVisible();
+    await expect(page.locator('.rack .tile')).toHaveCount(0);
+
+    // A wrong PIN keeps it locked; the right PIN reveals the full rack.
+    await page.locator('.unlock').click();
+    await typePin(page, '0000');
+    await expect(page.locator('.pad')).toBeVisible(); // still open after a wrong PIN
+    await typePin(page, '1234');
+    await expect(page.locator('.rack .tile')).toHaveCount(7);
+
+    // Opening the history reveals NO social controls on the seat plaques (a local game is
+    // account-less), and the Dictionary entry (the comms button) is kept for the active game.
+    await page.locator('.scoreboard').click();
+    await expect(page.locator('.fico')).toHaveCount(0);
+    await expect(page.locator('.chat-ico')).toBeVisible();
+    await page.locator('.scoreboard').click();
+
+    // Host override: 🔐 -> master PIN -> skip the current turn -> confirm. The turn passes to Bob,
+    // whose seat is open, so his rack shows without a lock.
+    await page.locator('button.tab', { hasText: /Host|Ведущий/ }).click();
+    await typePin(page, '9999');
+    await page.getByRole('button', { name: /Skip|Пропустить/ }).click();
+    await page.getByRole('button', { name: /^(OK|ОК)$/ }).click();
+    await expect(page.locator('.unlock')).toHaveCount(0);
+    await expect(page.locator('.rack .tile')).toHaveCount(7);
+
+    // Back in the lobby the active hotseat game has a kebab; terminating it needs the master PIN.
+    await page.getByRole('button', { name: /Back|Назад/i }).click();
+    await expect(page.getByText('Ann', { exact: false }).first()).toBeVisible();
+    await expect(page.locator('.rowwrap')).toHaveCount(1);
+    await page.locator('.kebab').first().click();
+    const del = page.locator('.rowwrap.revealed .del');
+    await expect(del).toBeVisible();
+    await del.click();
+    await typePin(page, '9999');
+    await expect(page.locator('.rowwrap')).toHaveCount(0);
+  });
+});

ui/e2e/install.spec.ts

@@ -0,0 +1,59 @@
+import { expect, test } from './fixtures';
+
+// The install CTA (components/InstallApp.svelte) is platform-adaptive: a one-tap button where the
+// browser offers a beforeinstallprompt (Chromium), a manual instructions modal on iOS Safari, and
+// nothing elsewhere / once installed / inside a Mini App. The native OS install dialog is
+// browser-level and not drivable from Playwright, so these assert the CTA's presence and branch.
+
+const IPHONE_SAFARI =
+  'Mozilla/5.0 (iPhone; CPU iPhone OS 17_0 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.0 Mobile/15E148 Safari/604.1';
+
+test('web: a captured install prompt shows the one-tap CTA and clicking it prompts', async ({ page }) => {
+  await page.goto('/');
+  // The web login screen is shown (an ordinary browser tab, not a Mini App).
+  await expect(page.getByRole('button', { name: /guest/i })).toBeVisible();
+
+  // Hidden until the browser offers installation (Playwright never fires beforeinstallprompt).
+  await expect(page.getByRole('button', { name: /Install the app/i })).toHaveCount(0);
+
+  // Simulate Chromium offering the install: dispatch a beforeinstallprompt the app can capture.
+  await page.evaluate(() => {
+    const e = new Event('beforeinstallprompt') as Event & {
+      prompt?: () => Promise<void>;
+      userChoice?: Promise<unknown>;
+    };
+    (window as unknown as { __promptCalled: boolean }).__promptCalled = false;
+    e.prompt = () => {
+      (window as unknown as { __promptCalled: boolean }).__promptCalled = true;
+      return Promise.resolve();
+    };
+    e.userChoice = Promise.resolve({ outcome: 'accepted', platform: '' });
+    window.dispatchEvent(e);
+  });
+
+  const cta = page.getByRole('button', { name: /Install the app/i });
+  await expect(cta).toBeVisible();
+  await cta.click();
+  // Clicking calls the captured prompt (the native dialog itself is not observable here).
+  await expect
+    .poll(() => page.evaluate(() => (window as unknown as { __promptCalled: boolean }).__promptCalled))
+    .toBe(true);
+});
+
+test.describe('iOS Safari', () => {
+  test.use({ userAgent: IPHONE_SAFARI });
+
+  test('shows manual Add-to-Home-Screen instructions (no programmatic install)', async ({ page }) => {
+    await page.goto('/');
+    await expect(page.getByRole('button', { name: /guest/i })).toBeVisible();
+
+    // On iOS Safari the CTA shows at once (no beforeinstallprompt is ever fired there).
+    const cta = page.getByRole('button', { name: /Install the app/i });
+    await expect(cta).toBeVisible();
+    await cta.click();
+
+    // It opens the app's own instructions modal (not a native / Telegram popup).
+    await expect(page.getByRole('heading', { name: 'Add to Home Screen' })).toBeVisible();
+    await expect(page.getByText(/Tap the Share button/)).toBeVisible();
+  });
+});

ui/e2e/landing.spec.ts

@@ -46,3 +46,15 @@ test('the landing is a normal scrolling document (the SPA document-pin does not
   expect(state.shell).toBe(false);
   expect(state.bodyPosition).not.toBe('fixed');
 });
+
+// The web-version entry (/app/) is always present, alongside the build-var-gated Telegram/VK ones
+// (absent here, since e2e sets no VITE_* vars), each with a caption.
+test('the landing shows a web-version entry linking /app/, with a caption', async ({ page }) => {
+  await page.goto('/landing.html');
+  await expect(page.getByText(/Играй в «Эрудита»/)).toBeVisible(); // Russian by default
+
+  const web = page.getByRole('link', { name: 'Играть в браузере' });
+  await expect(web).toBeVisible();
+  expect(await web.getAttribute('href')).toContain('/app/');
+  await expect(page.getByText('Веб-версия')).toBeVisible();
+});

ui/e2e/offline.spec.ts

@@ -0,0 +1,95 @@
+import { test, expect, type Page } from './fixtures';
+
+// The offline mode is gated to an installed standalone PWA with a confirmed email. The mock account
+// has an email; force the standalone display mode so the Settings offline toggle is offered. Only the
+// `(display-mode: standalone)` query is overridden — theme/reduce-motion queries pass through.
+async function forceStandalone(page: Page): Promise<void> {
+  await page.addInitScript(() => {
+    const orig = window.matchMedia.bind(window);
+    window.matchMedia = (q: string) =>
+      (q.includes('display-mode: standalone')
+        ? { matches: true, media: q, onchange: null, addEventListener() {}, removeEventListener() {}, addListener() {}, removeListener() {}, dispatchEvent: () => false }
+        : orig(q)) as MediaQueryList;
+  });
+}
+
+// After a load, land in the lobby. The mock cold-starts on the login screen (no seeded session), so
+// click through as guest. Waiting for the button (rather than a point-in-time count()) is what makes
+// this deterministic: a count() sampled during the pre-login splash frame returned 0, skipped the
+// click, and then hung — or latched a transient lobby tab-bar — instead of opening the real lobby.
+async function enterLobby(page: Page): Promise<void> {
+  await page.getByRole('button', { name: /guest|гост/i }).first().click();
+  // The lobby tab bar has three tabs in a fixed order: New (0), Stats (1), Settings (2). nth() is
+  // robust to locale, emoji variation selectors and the coachmark anchors (which the first-run
+  // onboarding strips after it completes).
+  await expect(page.locator('button.tab').nth(2)).toBeVisible();
+}
+
+// Pick a rack tile by its glyph and drop it on a board square (the rack of the pinned-seed game has
+// all-distinct letters, so the glyph is unambiguous).
+async function placeTile(page: Page, glyph: string, row: number, col: number): Promise<void> {
+  await page.locator('.rack .tile', { hasText: glyph }).first().click();
+  await page.locator(`[data-cell][data-row="${row}"][data-col="${col}"]`).click();
+}
+
+test.describe('offline mode', () => {
+  test('enter via the toggle, play a local vs_ai game, persist across a reload', async ({ page }) => {
+    await forceStandalone(page);
+    await page.goto('/');
+    await enterLobby(page);
+
+    // Online: a seeded online game (vs Ann) is listed.
+    await expect(page.getByText('Ann', { exact: false }).first()).toBeVisible();
+
+    // Enter offline through the real Settings toggle (its readiness check fetches every enabled
+    // variant's dawg, served from /e2edict/ by the mock) — the header turns blue with the chip.
+    await page.locator('button.tab').nth(2).click();
+    await page.getByRole('button', { name: /^(Offline|Оффлайн)$/ }).click();
+    await expect(page.locator('header.nav.offline')).toBeVisible({ timeout: 15000 });
+
+    // Back in the (now offline) lobby: the online games are hidden and the Stats tab is disabled.
+    await page.getByRole('button', { name: /Back|Назад/i }).click();
+    await expect(page.locator('button.tab').nth(2)).toBeVisible();
+    await expect(page.getByText('Ann', { exact: false })).toHaveCount(0);
+    await expect(page.locator('button.tab').nth(1)).toBeDisabled();
+
+    // Create a device-local English vs_ai game with a pinned bag seed (deals the rack NEWYMAO).
+    await page.evaluate(() => (window as unknown as { __mock: { setLocalSeed(s: string): void } }).__mock.setLocalSeed('1'));
+    await page.locator('button.tab').nth(0).click();
+    // The English variant's display name is "Scrabble" (Latin) in both locales — the Russian
+    // variants are "Скрэббл"/"Эрудит"/"Erudite", so this uniquely selects the English game.
+    await page.locator('.variant', { hasText: 'Scrabble' }).click();
+    await page.locator('button.invite').click();
+    await expect(page.locator('[data-cell]').first()).toBeVisible();
+
+    // The human's first move is not idle-gated: the hint is available at once (no 🔒 lock badge).
+    await expect(page.locator('.lock')).toHaveCount(0);
+
+    // The human plays WAY horizontally across the centre (7,5)-(7,7).
+    await placeTile(page, 'W', 7, 5);
+    await placeTile(page, 'A', 7, 6);
+    await placeTile(page, 'Y', 7, 7);
+    await expect(page.locator('[data-cell].pending')).toHaveCount(3);
+    await page.locator('.make').click();
+
+    // The play commits and the local robot replies with a real move, so the board carries more than
+    // WAY's three tiles.
+    await expect(async () => {
+      expect(await page.locator('[data-cell].filled').count()).toBeGreaterThan(3);
+    }).toPass({ timeout: 15000 });
+    const filled = await page.locator('[data-cell].filled').count();
+
+    // Now it is the human's turn again after the robot moved: the idle hint gate arms, so the hint
+    // button shows the 🔒 lock (it lifts after 30 idle minutes on a monotonic clock — not waited here).
+    await expect(page.locator('.lock')).toBeVisible();
+
+    // Reload: the hash router restores the /game/<id> route and the local game replays from
+    // IndexedDB with every committed tile intact.
+    await page.reload();
+    await expect(page.locator('[data-cell]').first()).toBeVisible();
+    await expect(page.locator('[data-cell].filled')).toHaveCount(filled);
+    // The idle-hint gate is persisted (a wall-clock unlock time), so the 🔒 survives the reload —
+    // the wait was not reset by relaunching.
+    await expect(page.locator('.lock')).toBeVisible();
+  });
+});

ui/e2e/router.spec.ts

@@ -0,0 +1,26 @@
+import { expect, test } from './fixtures';
+
+// The hash router must update its reactive `route` rune synchronously inside navigate(), not defer it
+// to the asynchronous `hashchange` event. Bootstrap flips `app.ready` in the same tick right after
+// `navigate('/login')` on an unauthenticated cold start; a route that trailed the hash for one frame
+// let App.svelte render the stale route (the empty-hash lobby) under the new login screen — a visible
+// lobby-shell flash plus a doomed games.list. It also made the offline e2e flaky: enterLobby could
+// latch that transient lobby tab-bar instead of clicking through the login screen.
+
+test('navigate updates the reactive route synchronously (no hashchange lag)', async ({ page }) => {
+  await page.goto('/');
+  // The bundle has loaded and installed the mock __router seam once the login screen is up.
+  await expect(page.getByRole('button', { name: /guest/i })).toBeVisible();
+
+  // Read the route in the SAME microtask as the navigate: the fix makes it the new route at once;
+  // the pre-fix code returned the previous route (it waited for the async hashchange).
+  const routeAfterNavigate = await page.evaluate(() => {
+    const r = (window as unknown as { __router: { navigate(p: string): void; route(): string } }).__router;
+    r.navigate('/settings');
+    return r.route();
+  });
+  expect(routeAfterNavigate).toBe('settings');
+
+  // The hash was written too, so a reload/back still resolves the same route.
+  expect(new URL(page.url()).hash).toBe('#/settings');
+});

ui/e2e/viewport.spec.ts

@@ -0,0 +1,69 @@
+import { test, expect, type Page } from './fixtures';
+
+// Playwright's WebKit has no real soft keyboard, so emulate iOS's visual-viewport behaviour: replace
+// window.visualViewport with a controllable fake BEFORE the app boots. The app's syncViewport
+// (app.svelte.ts) reads visualViewport.height/offsetTop and mirrors them into --vvh / --vv-top, which
+// position the pinned app-shell (app.css html.app-shell body). Driving the fake exercises the exact
+// code path the real keyboard triggers on iOS — where the layout viewport does NOT shrink and the
+// visual viewport instead offsets down toward the focused field.
+async function installFakeViewport(page: Page): Promise<void> {
+  await page.addInitScript(() => {
+    const fake = new EventTarget() as EventTarget & { height: number; offsetTop: number; width: number };
+    fake.height = window.innerHeight;
+    fake.offsetTop = 0;
+    fake.width = window.innerWidth;
+    Object.defineProperty(window, 'visualViewport', { configurable: true, value: fake });
+    (window as unknown as { __vv: typeof fake }).__vv = fake;
+  });
+}
+
+async function setViewport(page: Page, height: number, offsetTop: number): Promise<void> {
+  await page.evaluate(
+    ([h, t]) => {
+      const vv = (window as unknown as { __vv: { height: number; offsetTop: number; dispatchEvent(e: Event): boolean } }).__vv;
+      vv.height = h;
+      vv.offsetTop = t;
+      vv.dispatchEvent(new Event('resize'));
+      vv.dispatchEvent(new Event('scroll'));
+    },
+    [height, offsetTop],
+  );
+}
+
+async function shell(page: Page): Promise<{ vvh: string; top: string; bodyTop: string }> {
+  return page.evaluate(() => ({
+    vvh: getComputedStyle(document.documentElement).getPropertyValue('--vvh').trim(),
+    top: getComputedStyle(document.documentElement).getPropertyValue('--vv-top').trim(),
+    bodyTop: getComputedStyle(document.body).top,
+  }));
+}
+
+test.describe('visual-viewport shell (soft-keyboard alignment)', () => {
+  test('the pinned shell follows the visual viewport height AND offset', async ({ page }) => {
+    await installFakeViewport(page);
+    await page.goto('/');
+    await expect(page.locator('html.app-shell')).toBeAttached();
+    const innerH = await page.evaluate(() => window.innerHeight);
+
+    // Keyboard closed: full height, no offset.
+    await setViewport(page, innerH, 0);
+    let s = await shell(page);
+    expect(s.top).toBe('0px');
+    expect(s.bodyTop).toBe('0px');
+
+    // Keyboard open + iOS offset: the visual viewport shrinks AND offsets down. The pinned shell must
+    // follow BOTH — the body's top must equal the offset (not stay at 0), else the top-anchored
+    // content shows empty space below (the iOS bug this fixes).
+    await setViewport(page, innerH - 300, 180);
+    s = await shell(page);
+    expect(s.vvh).toBe(`${innerH - 300}px`);
+    expect(s.top).toBe('180px');
+    expect(s.bodyTop).toBe('180px');
+
+    // Keyboard closed again: the offset reverts to 0 — no stale shift left behind.
+    await setViewport(page, innerH, 0);
+    s = await shell(page);
+    expect(s.top).toBe('0px');
+    expect(s.bodyTop).toBe('0px');
+  });
+});

ui/index.html

@@ -256,6 +256,18 @@
     <link rel="icon" href="favicon.ico" sizes="32x32" />
     <link rel="icon" type="image/svg+xml" href="favicon.svg" />
     <link rel="apple-touch-icon" href="apple-touch-icon.png" />
+    <!-- PWA installability (web /app/ only): the manifest + a service worker (registered from
+         lib/pwa, web-only) let the app be added to the home screen / desktop. The relative href
+         resolves per serving path; these tags are inert inside the Telegram/VK Mini App webviews,
+         which manage their own chrome. theme-color mirrors the light/dark --bg tokens (app.css). -->
+    <link rel="manifest" href="manifest.webmanifest" />
+    <meta name="theme-color" content="#f3f4f6" media="(prefers-color-scheme: light)" />
+    <meta name="theme-color" content="#0f1115" media="(prefers-color-scheme: dark)" />
+    <meta name="mobile-web-app-capable" content="yes" />
+    <meta name="apple-mobile-web-app-capable" content="yes" />
+    <meta name="apple-mobile-web-app-status-bar-style" content="default" />
+    <meta name="apple-mobile-web-app-title" content="Эрудит" />
+    <meta name="application-name" content="Эрудит" />
   </head>
   <body>
     <div id="app"></div>

ui/package.json

@@ -32,6 +32,10 @@
     "svelte-check": "^4.1.0",
     "typescript": "^5.7.0",
     "vite": "^6.0.0",
-    "vitest": "^3.0.0"
+    "vite-plugin-pwa": "^0.21.2",
+    "vitest": "^3.0.0",
+    "workbox-core": "^7.4.1",
+    "workbox-precaching": "^7.4.1",
+    "workbox-routing": "^7.4.1"
   }
 }

ui/playwright.config.ts

@@ -21,8 +21,11 @@ export default defineConfig({
     // under /app/ and /telegram/): served from the preview root, an absolute base keeps assets at
     // /assets/ so the SPA-fallback also boots a subpath like /telegram/. Base only prefixes asset
     // URLs, so the minified JS under test is identical to the contour's.
+    // After the mock build, copy the real per-variant dawgs into the preview output (dist-e2e) so the
+    // offline spec can play a real local vs_ai game; the files are e2e-only (never committed, never in
+    // the production build). Source: E2E_DICT_DIR (CI: the fetched release; local: the sibling).
     command:
-      'pnpm exec vite build --mode mock --base / --outDir dist-e2e --emptyOutDir && pnpm exec vite preview --outDir dist-e2e --port 4173 --strictPort',
+      'pnpm exec vite build --mode mock --base / --outDir dist-e2e --emptyOutDir && node scripts/e2e-dict.mjs && pnpm exec vite preview --outDir dist-e2e --port 4173 --strictPort',
     url: 'http://localhost:4173',
     reuseExistingServer: !process.env.CI,
     timeout: 120_000,

ui/public/manifest.webmanifest

@@ -0,0 +1,17 @@
+{
+  "name": "Эрудит (Скрэббл)",
+  "short_name": "Эрудит",
+  "description": "Игра в слова «Эрудит» (Скрэббл): играйте с друзьями, случайным соперником или ИИ-роботом.",
+  "lang": "ru",
+  "dir": "ltr",
+  "start_url": ".",
+  "scope": ".",
+  "display": "standalone",
+  "background_color": "#f3f4f6",
+  "theme_color": "#f3f4f6",
+  "icons": [
+    { "src": "icon-192.png", "sizes": "192x192", "type": "image/png", "purpose": "any" },
+    { "src": "icon-512.png", "sizes": "512x512", "type": "image/png", "purpose": "any" },
+    { "src": "icon-maskable-512.png", "sizes": "512x512", "type": "image/png", "purpose": "maskable" }
+  ]
+}

ui/scripts/bundle-size.mjs

@@ -19,10 +19,17 @@ import { join } from 'node:path';
 
 const DIST = 'dist';
 
-// Per-chunk gzip budgets in KB. The app entry was raised to 110 when the local
+// Per-chunk gzip budgets in KB. The app entry was raised to 110 for the local move-preview
-// move-preview wiring landed (the heavy dict subsystem stays in lazy chunks; this
+// wiring, to 112 for the PWA install feature, to 113 for the offline-mode wiring, to 114 for
-// covers the small in-entry game/debug wiring it needs).
+// the offline auto-detect (the cold-start reachability check and the "no connection" dialog live in
-const BUDGET = { app: 110, shared: 30, landing: 5 };
+// the boot path), then to 115 for the vs_ai idle-hint gate — its monotonic clock, lock badge and
+// countdown toast live in the always-loaded game screen (Game.svelte) — and to 120 for the offline
+// pass-and-play (hotseat) mode: the on-screen PIN pad, the creation roster and the in-game host menu
+// live in the always-loaded New Game / Game / Lobby screens (the offline engine and the tiny PIN
+// hashing stay in lazy chunks / are negligible). The heavy parts — the dict loader, the move
+// generator and the preload orchestration — still stay in lazy chunks. Scoped CSS lands in the CSS
+// chunk, not this JS budget.
+const BUDGET = { app: 120, shared: 30, landing: 5 };
 
 // gzipped returns the gzipped byte size of a built asset, or 0 when the reference is not a
 // local file (e.g. the Telegram SDK loaded from a CDN) or is missing.

ui/scripts/e2e-dict.mjs

@@ -0,0 +1,35 @@
+// Copies the real per-variant dictionary DAWGs into the mock e2e preview output (dist-e2e/e2edict/)
+// so the offline spec can create and play a real local vs_ai game (the mock's fetchDict serves these
+// files — see lib/mock/client.ts). The dawgs are NEVER committed and never enter the production
+// build; they live only in the throwaway dist-e2e/ that `vite preview` serves for Playwright.
+//
+// Source directory: E2E_DICT_DIR — in CI the fetched scrabble-dictionary release
+// ($GITHUB_WORKSPACE/dawg); locally it defaults to the sibling scrabble-solver/dawg checkout. A
+// missing source only warns (so the other, dawg-free specs still run); the offline spec then fails
+// with an obvious HTTP 404 from fetchDict.
+
+import { existsSync, mkdirSync, copyFileSync } from 'node:fs';
+import { join } from 'node:path';
+
+const srcDir = process.env.E2E_DICT_DIR ?? '../../scrabble-solver/dawg';
+const outDir = 'dist-e2e/e2edict';
+
+// The app's Variant enum value -> the release dawg file name (matches the movegen/parity mapping).
+const dawgFor = {
+  scrabble_en: 'en_sowpods',
+  scrabble_ru: 'ru_scrabble',
+  erudit_ru: 'ru_erudit',
+};
+
+mkdirSync(outDir, { recursive: true });
+let copied = 0;
+for (const [variant, file] of Object.entries(dawgFor)) {
+  const src = join(srcDir, `${file}.dawg`);
+  if (!existsSync(src)) {
+    console.warn(`e2e-dict: missing ${src} — the offline spec will 404 (set E2E_DICT_DIR)`);
+    continue;
+  }
+  copyFileSync(src, join(outDir, `${variant}.dawg`));
+  copied++;
+}
+console.log(`e2e-dict: copied ${copied}/${Object.keys(dawgFor).length} dawgs from ${srcDir} -> ${outDir}`);

ui/src/App.svelte

@@ -1,7 +1,7 @@
 <script lang="ts">
   import { onMount } from 'svelte';
   import { cubicOut } from 'svelte/easing';
-  import { app, bootstrap } from './lib/app.svelte';
+  import { app, bootstrap, resolveOfflinePrompt } from './lib/app.svelte';
   import { router, type RouteName } from './lib/router.svelte';
   import { t } from './lib/i18n/index.svelte';
   import Toast from './components/Toast.svelte';
@@ -136,6 +136,21 @@
 <Coachmark />
 <MaintenanceOverlay />
 
+<!-- Cold-start "no connection" dialog: the reachability check timed out with the network interface
+     reportedly online, so it is ambiguous. The player chooses to go offline (play local vs_ai) or to
+     keep trying to connect. bootstrap awaits this choice (app.offlinePrompt). -->
+{#if app.offlinePrompt}
+  <div class="offprompt" role="dialog" aria-modal="true">
+    <div class="card">
+      <p class="msg">{t('offline.promptTitle')}</p>
+      <div class="acts">
+        <button class="opt primary" onclick={() => resolveOfflinePrompt(true)}>{t('offline.promptYes')}</button>
+        <button class="opt" onclick={() => resolveOfflinePrompt(false)}>{t('offline.promptNo')}</button>
+      </div>
+    </div>
+  </div>
+{/if}
+
 {#if routeIsLobby && !app.splashDone && !app.blocked && !app.bootError && !app.launchError}
   <Splash />
 {/if}
@@ -145,6 +160,49 @@
 {/if}
 
 <style>
+  /* The cold-start "no connection" dialog — a centred card over a scrim, above the splash. */
+  .offprompt {
+    position: fixed;
+    inset: 0;
+    z-index: 100;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    background: rgba(0, 0, 0, 0.5);
+    padding: var(--pad);
+  }
+  .offprompt .card {
+    background: var(--bg-elev);
+    border: 1px solid var(--border);
+    border-radius: var(--radius-sm);
+    padding: 20px;
+    max-width: 320px;
+    width: 100%;
+    text-align: center;
+  }
+  .offprompt .msg {
+    margin: 0 0 16px;
+    font-size: 1rem;
+    color: var(--text);
+  }
+  .offprompt .acts {
+    display: flex;
+    flex-direction: column;
+    gap: 8px;
+  }
+  .offprompt .opt {
+    padding: 11px 16px;
+    border: 1px solid var(--border);
+    border-radius: var(--radius-sm);
+    background: var(--surface);
+    color: var(--text);
+    font-size: 0.95rem;
+  }
+  .offprompt .opt.primary {
+    background: var(--accent);
+    color: var(--accent-text);
+    border-color: var(--accent);
+  }
   .splash {
     height: 100%;
     display: grid;

ui/src/Landing.svelte

@@ -80,20 +80,26 @@
   <section class="hero">
     <h1>{about.title}</h1>
     <p class="tagline">{t('landing.tagline')}</p>
-    {#if tgLink || vkLink}
+    <!-- Platform entries: Telegram/VK are gated by their build vars; the web version (/app/) is
-      <div class="entries">
+         always available. A caption under each clarifies what it opens. -->
-        {#if tgLink}
+    <div class="entries">
-          <a class="entry" href={tgLink} target="_blank" rel="noopener noreferrer" aria-label={t('landing.playTelegram')}>
+      {#if tgLink}
-            <img src="telegram-logo.svg" alt="" width="64" height="64" />
+        <a class="entry" href={tgLink} target="_blank" rel="noopener noreferrer" aria-label={t('landing.playTelegram')}>
-          </a>
+          <img src="telegram-logo.svg" alt="" width="64" height="64" />
-        {/if}
+          <span class="caption">{t('landing.captionTelegram')}</span>
-        {#if vkLink}
+        </a>
-          <a class="entry" href={vkLink} target="_blank" rel="noopener noreferrer" aria-label={t('landing.playVK')}>
+      {/if}
-            <img src="vk-logo.svg" alt="" width="64" height="64" />
+      {#if vkLink}
-          </a>
+        <a class="entry" href={vkLink} target="_blank" rel="noopener noreferrer" aria-label={t('landing.playVK')}>
-        {/if}
+          <img src="vk-logo.svg" alt="" width="64" height="64" />
-      </div>
+          <span class="caption">{t('landing.captionVK')}</span>
-    {/if}
+        </a>
+      {/if}
+      <a class="entry" href="/app/" aria-label={t('landing.playWeb')}>
+        <img src="favicon.svg" alt="" width="64" height="64" />
+        <span class="caption">{t('landing.captionWeb')}</span>
+      </a>
+    </div>
   </section>
 
   <section class="info">
@@ -207,8 +213,8 @@
     color: var(--text-muted);
     font-size: 1.05rem;
   }
-  /* The platform entries are just the bigger logos in a row (no button chrome, no captions);
+  /* The platform entries are the bigger logos in a row, each with a short caption below; the
-     each link keeps an aria-label for assistive tech. */
+     link keeps an aria-label for assistive tech. */
   .entries {
     align-self: center;
     display: flex;
@@ -217,6 +223,11 @@
   }
   .entry {
     display: inline-flex;
+    flex-direction: column;
+    align-items: center;
+    gap: 8px;
+    text-decoration: none;
+    color: var(--text);
   }
   .entry img {
     display: block;
@@ -225,6 +236,10 @@
   .entry:hover img {
     transform: scale(1.06);
   }
+  .caption {
+    font-size: 0.9rem;
+    color: var(--text-muted);
+  }
   .info {
     background: var(--surface-2);
     border-radius: var(--radius-sm);

ui/src/app.css

@@ -162,7 +162,15 @@ html.app-shell {
 }
 html.app-shell body {
   position: fixed;
-  inset: 0;
+  /* Follow the visual viewport (top + height), not merely fill the layout viewport: iOS Safari /
+     WKWebView does not shrink the layout viewport for the soft keyboard — it offsets the visual
+     viewport down toward the focused field — so a top-anchored (inset:0) shell would misalign, showing
+     empty space below the content (worst on a repeat focus). --vv-top / --vvh are kept in sync from
+     app.svelte.ts (syncViewport). The fallbacks equal inset:0 before the first sync / on the landing. */
+  top: var(--vv-top, 0px);
+  left: 0;
+  right: 0;
+  height: var(--vvh, 100%);
   overflow: hidden;
 }
 

ui/src/components/Header.svelte

@@ -1,6 +1,7 @@
 <script lang="ts">
   import { navigate } from '../lib/router.svelte';
   import { connection } from '../lib/connection.svelte';
+  import { offlineMode, dictPreloadWarning } from '../lib/offline.svelte';
   import { t } from '../lib/i18n/index.svelte';
   import { app, openDebug } from '../lib/app.svelte';
   import Spinner from './Spinner.svelte';
@@ -27,7 +28,7 @@
   }
 </script>
 
-<header class="nav" class:grow>
+<header class="nav" class:grow class:offline={offlineMode.active}>
   <div class="bar">
     {#if showBack}
       <button class="icon back" onclick={() => back && navigate(back)} aria-label="Back">
@@ -36,15 +37,20 @@
     {:else}
       <span class="spacer"></span>
     {/if}
-    {#if connection.online}
+    {#if connection.online || offlineMode.active}
       <!-- svelte-ignore a11y_click_events_have_key_events -->
       <!-- svelte-ignore a11y_no_noninteractive_element_interactions -->
       <h1 onclick={onTitleTap}>{title}</h1>
     {:else}
       <h1 class="connecting"><Spinner /> <span>{t('connection.connecting')}</span></h1>
     {/if}
-    <!-- A right-hand spacer balances the back button so the title stays centred. -->
+    <!-- A right-hand spacer balances the back button so the title stays centred; in offline mode it
-    <span class="spacer"></span>
+         carries the "Offline" chip so the deliberate mode is always visible (not just the blue tint). -->
+    {#if offlineMode.active}
+      <span class="chip">{t('settings.offline')}</span>
+    {:else}
+      <span class="spacer"></span>
+    {/if}
   </div>
   <!-- The ad banner lives inside the nav, directly under the title bar, so it sits in the
        same place on every screen — and in the game (grown nav) the spare height falls below
@@ -52,7 +58,11 @@
        coachmark overlay is up (app.coachActive) so the scrolling strip does not run behind the
        dimmed onboarding layer; the engine keeps rotating (module scope) and the strip reappears,
        per this same condition, once onboarding closes. -->
-  {#if app.profile?.banner && app.profile.banner.campaigns.length && !app.coachActive}
+  {#if dictPreloadWarning.active}
+    <!-- A background dictionary preload for offline readiness failed (poor connection): a soft
+         notice takes the ad banner's slot until a later preload succeeds and clears it. -->
+    <p class="preload-warn" role="alert">{t('offline.preloadWarning')}</p>
+  {:else if app.profile?.banner && app.profile.banner.campaigns.length && !app.coachActive}
     <AdBanner
       campaigns={app.profile.banner.campaigns}
       timings={app.profile.banner.timings}
@@ -74,6 +84,12 @@
     user-select: none;
     -webkit-user-select: none;
   }
+  /* Deliberate offline mode: a blue-tinted nav, mixed from the accent so it tracks the light/dark
+     theme (and any Telegram theme override) — the offline state is unmistakable at a glance. */
+  .nav.offline {
+    background: color-mix(in srgb, var(--accent) 20%, var(--bg-elev));
+    border-bottom-color: color-mix(in srgb, var(--accent) 35%, var(--border));
+  }
   .nav.grow {
     /* Grow into spare height (banner under the title, the board pinned to the bottom), but
        never shrink: on a short viewport the banner keeps its height and the board's own
@@ -114,6 +130,34 @@
     align-items: center;
     justify-content: center;
   }
+  /* The offline chip: a compact accent-tinted pill in the header's right slot. */
+  .chip {
+    min-width: 40px;
+    height: 24px;
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    padding: 0 8px;
+    font-size: 0.72rem;
+    font-weight: 600;
+    color: var(--accent);
+    background: color-mix(in srgb, var(--accent) 16%, transparent);
+    border: 1px solid color-mix(in srgb, var(--accent) 45%, transparent);
+    border-radius: 999px;
+    white-space: nowrap;
+  }
+  /* The offline-readiness preload warning: a soft, muted strip in the ad banner's slot, sized like
+     the banner region so the bar does not jump when it appears. */
+  .preload-warn {
+    margin: 0;
+    padding: 7px var(--pad);
+    font-size: 0.78rem;
+    line-height: 1.3;
+    text-align: center;
+    color: var(--text-muted);
+    background: var(--surface-2);
+    border-top: 1px solid var(--border);
+  }
   .back {
     background: none;
     border: none;

ui/src/components/InstallApp.svelte

@@ -0,0 +1,85 @@
+<script lang="ts">
+  import { t } from '../lib/i18n/index.svelte';
+  import { installMode, promptInstall } from '../lib/pwa.svelte';
+  import Modal from './Modal.svelte';
+
+  // Platform-adaptive: 'oneTap' fires the native Chromium install dialog; 'iosInstructions' opens
+  // the manual Share -> Add-to-Home-Screen guide (iOS Safari has no programmatic install); 'hidden'
+  // renders nothing (already installed, inside a Telegram/VK Mini App, or an unsupported browser).
+  const mode = $derived(installMode());
+  let showIos = $state(false);
+
+  function onClick(): void {
+    // promptInstall must run synchronously from this gesture — the deferred prompt is gated on it.
+    if (mode === 'oneTap') void promptInstall();
+    else if (mode === 'iosInstructions') showIos = true;
+  }
+</script>
+
+{#if mode !== 'hidden'}
+  <button type="button" class="install" onclick={onClick}>
+    <img src="favicon.svg" alt="" width="40" height="40" />
+    <span class="text">
+      <span class="title">{t('install.title')}</span>
+      <span class="subtitle">{t('install.subtitle')}</span>
+    </span>
+  </button>
+{/if}
+
+{#if showIos}
+  <Modal title={t('install.iosTitle')} onclose={() => (showIos = false)}>
+    <ol class="steps">
+      <li>{t('install.iosStep1')}</li>
+      <li>{t('install.iosStep2')}</li>
+      <li>{t('install.iosStep3')}</li>
+    </ol>
+    <button type="button" class="ok" onclick={() => (showIos = false)}>{t('common.ok')}</button>
+  </Modal>
+{/if}
+
+<style>
+  .install {
+    display: flex;
+    align-items: center;
+    gap: 12px;
+    width: 100%;
+    text-align: left;
+    padding: 12px;
+    border: 1px solid var(--border);
+    border-radius: var(--radius-sm);
+    background: var(--surface);
+    color: var(--text);
+    cursor: pointer;
+  }
+  .install img {
+    flex: none;
+    border-radius: 8px;
+  }
+  .text {
+    display: flex;
+    flex-direction: column;
+    gap: 2px;
+    min-width: 0;
+  }
+  .title {
+    font-weight: 600;
+  }
+  .subtitle {
+    font-size: 0.85rem;
+    color: var(--text-muted);
+    line-height: 1.35;
+  }
+  .steps {
+    margin: 0 0 16px;
+    padding-left: 1.25rem;
+    line-height: 1.6;
+  }
+  .ok {
+    width: 100%;
+    padding: 10px 12px;
+    border: 1px solid var(--accent);
+    background: var(--accent);
+    color: var(--accent-text);
+    border-radius: var(--radius-sm);
+  }
+</style>

ui/src/components/PinPad.svelte

@@ -0,0 +1,268 @@
+<script lang="ts">
+  // Apple-lock-screen-style 4-digit PIN pad for offline pass-and-play (hotseat) games.
+  // Modes:
+  //   set     — enter a PIN, then repeat it to confirm; emits { kind: 'set', lock }.
+  //   verify  — enter a PIN; runs `verify(pin)` on the 4th digit; emits { kind: 'verified' }
+  //             or shakes + clears on a wrong PIN.
+  //   change  — run `verify` on the current PIN, then offer "set a new PIN" (the set flow)
+  //             or, when allowRemove, "remove PIN" ({ kind: 'removed' }).
+  // Verification is delegated to the caller's `verify` callback: at creation time it checks a
+  // UI-held lock (lib/pin verifyPin); in-game it delegates to the local source (which holds the
+  // stored lock). The pad never shows an OK button: entering the 4th digit is the action. PIN
+  // storage is a social lock, not cryptography — see lib/pin.ts.
+  import Modal from './Modal.svelte';
+  import { t } from '../lib/i18n/index.svelte';
+  import { newLock, type PinLock } from '../lib/pin';
+
+  /** PinResult is the outcome handed to onresult when the pad completes. */
+  export type PinResult =
+    | { kind: 'set'; lock: PinLock }
+    | { kind: 'verified' }
+    | { kind: 'removed' };
+
+  let {
+    mode,
+    title = '',
+    verify,
+    allowRemove = false,
+    onclose,
+    onresult,
+  }: {
+    mode: 'set' | 'verify' | 'change';
+    title?: string;
+    /** Verifies an entered PIN (required for 'verify' and 'change'). */
+    verify?: (pin: string) => Promise<boolean>;
+    allowRemove?: boolean;
+    onclose?: () => void;
+    onresult: (r: PinResult) => void;
+  } = $props();
+
+  const LEN = 4;
+
+  // 'old' verifies the existing PIN (change); 'menu' offers set-new / remove (change);
+  // 'enter' collects a PIN; 'confirm' re-enters it (set / change→new). `mode` is fixed
+  // for the pad's lifetime (callers mount a fresh pad per operation), so capturing its
+  // initial value here is intentional.
+  // svelte-ignore state_referenced_locally
+  let phase = $state<'old' | 'menu' | 'enter' | 'confirm'>(mode === 'change' ? 'old' : 'enter');
+  let buffer = $state('');
+  let first = $state(''); // the first entry, awaiting confirmation
+  let error = $state(false); // drives the error prompt + shake
+  let shakeSeq = $state(0); // bumped on each error to replay the shake animation
+  let busy = $state(false); // guards the async check between the 4th digit and the outcome
+
+  function promptText(): string {
+    if (error) return phase === 'confirm' ? t('pin.mismatch') : t('pin.wrong');
+    switch (phase) {
+      case 'old':
+        return t('pin.enterCurrent');
+      case 'confirm':
+        return t('pin.repeat');
+      default:
+        return mode === 'verify' ? t('pin.enter') : t('pin.create');
+    }
+  }
+
+  function fail(): void {
+    buffer = '';
+    error = true;
+    shakeSeq += 1;
+  }
+
+  async function commit(): Promise<void> {
+    busy = true;
+    try {
+      // Let the 4th dot register before the verdict: a beat so the fill (and, on failure, the shake)
+      // reads as a deliberate response rather than an instant flicker.
+      await new Promise((r) => setTimeout(r, 250));
+      if (phase === 'old') {
+        if (verify && (await verify(buffer))) {
+          buffer = '';
+          error = false;
+          phase = 'menu';
+        } else fail();
+      } else if (phase === 'enter' && mode === 'verify') {
+        if (verify && (await verify(buffer))) onresult({ kind: 'verified' });
+        else fail();
+      } else if (phase === 'enter') {
+        first = buffer;
+        buffer = '';
+        error = false;
+        phase = 'confirm';
+      } else if (phase === 'confirm') {
+        if (buffer === first) onresult({ kind: 'set', lock: await newLock(buffer) });
+        else {
+          first = '';
+          phase = 'enter';
+          fail();
+        }
+      }
+    } finally {
+      busy = false;
+    }
+  }
+
+  function press(d: string): void {
+    if (busy || phase === 'menu' || buffer.length >= LEN) return;
+    error = false;
+    buffer += d;
+    if (buffer.length === LEN) void commit();
+  }
+
+  function back(): void {
+    if (busy || phase === 'menu') return;
+    buffer = buffer.slice(0, -1);
+  }
+
+  function startNew(): void {
+    error = false;
+    first = '';
+    buffer = '';
+    phase = 'enter';
+  }
+
+  function onkey(e: KeyboardEvent): void {
+    if (e.key >= '0' && e.key <= '9') {
+      press(e.key);
+      e.preventDefault();
+    } else if (e.key === 'Backspace') {
+      back();
+      e.preventDefault();
+    } else if (e.key === 'Escape') {
+      onclose?.();
+    }
+  }
+
+  const keys = ['1', '2', '3', '4', '5', '6', '7', '8', '9'];
+  const slots = Array.from({ length: LEN }, (_, i) => i);
+</script>
+
+<svelte:window onkeydown={onkey} />
+
+<Modal {title} {onclose} overlayKeyboard>
+  <div class="pad">
+    {#if phase === 'menu'}
+      <div class="menu">
+        <button class="opt" onclick={startNew}>{t('pin.setNew')}</button>
+        {#if allowRemove}
+          <button class="opt danger" onclick={() => onresult({ kind: 'removed' })}>
+            {t('pin.remove')}
+          </button>
+        {/if}
+      </div>
+    {:else}
+      <p class="prompt" class:err={error}>{promptText()}</p>
+      {#key shakeSeq}
+        <div class="dots" class:shake={error} aria-hidden="true">
+          {#each slots as i}
+            <span class="dot" class:on={i < buffer.length}></span>
+          {/each}
+        </div>
+      {/key}
+      <div class="grid">
+        {#each keys as k}
+          <button class="key" onclick={() => press(k)} aria-label={k}>{k}</button>
+        {/each}
+        <span class="key spacer"></span>
+        <button class="key" onclick={() => press('0')} aria-label="0">0</button>
+        <button class="key back" onclick={back} aria-label="⌫" disabled={buffer.length === 0}>⌫</button>
+      </div>
+    {/if}
+  </div>
+</Modal>
+
+<style>
+  .pad {
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    gap: 16px;
+    padding-top: 4px;
+  }
+  .prompt {
+    margin: 0;
+    font-size: 0.95rem;
+    color: var(--muted, var(--text));
+    min-height: 1.2em;
+  }
+  .prompt.err {
+    color: var(--danger);
+  }
+  .dots {
+    display: flex;
+    gap: 16px;
+  }
+  .dot {
+    width: 14px;
+    height: 14px;
+    border-radius: 50%;
+    border: 1.5px solid var(--text);
+    box-sizing: border-box;
+  }
+  .dot.on {
+    background: var(--text);
+  }
+  .shake {
+    animation: shake 0.32s ease;
+  }
+  @keyframes shake {
+    0%, 100% { transform: translateX(0); }
+    20% { transform: translateX(-7px); }
+    40% { transform: translateX(7px); }
+    60% { transform: translateX(-5px); }
+    80% { transform: translateX(5px); }
+  }
+  .grid {
+    display: grid;
+    grid-template-columns: repeat(3, 1fr);
+    gap: 12px;
+  }
+  .key {
+    width: 62px;
+    height: 62px;
+    border-radius: 50%;
+    border: 1px solid var(--border);
+    background: var(--surface);
+    color: var(--text);
+    font-size: 1.4rem;
+    font-weight: 500;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+  }
+  .key:active {
+    background: var(--accent);
+    color: var(--accent-text);
+  }
+  .key.back {
+    border-color: transparent;
+    background: transparent;
+    font-size: 1.2rem;
+  }
+  .key.back:disabled {
+    opacity: 0.3;
+  }
+  .key.spacer {
+    border: none;
+    background: none;
+    pointer-events: none;
+  }
+  .menu {
+    display: flex;
+    flex-direction: column;
+    gap: 10px;
+    width: 100%;
+  }
+  .opt {
+    padding: 14px;
+    border: 1px solid var(--border);
+    background: var(--surface);
+    color: var(--text);
+    border-radius: var(--radius);
+    font-weight: 600;
+  }
+  .opt.danger {
+    border-color: var(--danger);
+    color: var(--danger);
+  }
+</style>

ui/src/game/CheckScreen.svelte

@@ -1,6 +1,7 @@
 <script lang="ts">
   import { onMount } from 'svelte';
   import { gateway } from '../lib/gateway';
+  import { gameSource, isLocalGameId } from '../lib/gamesource';
   import { handleError, showToast } from '../lib/app.svelte';
   import { t } from '../lib/i18n/index.svelte';
   import { alphabetLetters } from '../lib/alphabet';
@@ -20,8 +21,10 @@
 
   onMount(async () => {
     try {
-      // Include the alphabet so input sanitising + the check accept the variant's letters.
+      // Include the alphabet so input sanitising + the check accept the variant's letters. Routed
-      const st = await gateway.gameState(id, true);
+      // through gameSource so an offline (local) game resolves its state from the device, not the
+      // network.
+      const st = await gameSource(id).gameState(id, true);
       variant = st.game.variant;
     } catch (e) {
       handleError(e);
@@ -41,7 +44,7 @@
     cooling = true;
     setTimeout(() => (cooling = false), 5000);
     try {
-      const r = await gateway.checkWord(id, w, variant);
+      const r = await gameSource(id).checkWord(id, w, variant);
       checked.set(w, r.legal);
       result = { word: w, legal: r.legal };
     } catch (e) {
@@ -77,7 +80,11 @@
         : t('game.wordIllegal', { word: result.word })}
     </p>
     <div class="actions">
-      <button class="complain" onclick={complain}>{t('game.complain')}</button>
+      <!-- Complaints go to the admin over the network; a local (offline) game has no backend to
+           receive them, so the control is dropped there. -->
+      {#if !isLocalGameId(id)}
+        <button class="complain" onclick={complain}>{t('game.complain')}</button>
+      {/if}
       {#if result.legal}
         <a
           class="lookup"

ui/src/game/CommsHub.svelte

@@ -16,15 +16,21 @@
   // The game is rendered (and cached) before its comms open, so the cache tells us whether
   // it is still active without another fetch; an unknown game keeps the Dictionary offered.
   const active = $derived(getCachedGame(id)?.view.game.status !== 'finished');
-  // An honest-AI game has no chat at all, so its hub is Dictionary-only.
+  // A local game has NO chat: an honest-AI game (vs_ai) and an offline pass-and-play (hotseat) game.
-  const vsAi = $derived(getCachedGame(id)?.view.game.vsAi ?? false);
+  // Its hub is Dictionary-only.
+  const chatless = $derived(
+    (getCachedGame(id)?.view.game.vsAi ?? false) || (getCachedGame(id)?.view.game.hotseat ?? false),
+  );
   // Seeded once from the entry route's tab, then owned locally. The effect keeps the tab valid:
-  // an AI game has only the Dictionary; a finished non-AI game has only Chat (a stale Dictionary
+  // a chatless game has only the Dictionary; a finished non-AI game has only Chat (a stale Dictionary
   // deep-link falls back to Chat).
+  // A chatless game starts on the Dictionary regardless of the entry route — this keeps ChatScreen
+  // (which fetches chat over the network) from mounting even for a beat, which would otherwise raise
+  // an error toast in offline mode.
   // svelte-ignore state_referenced_locally
-  let tab = $state<CommsTab>(initialTab);
+  let tab = $state<CommsTab>(chatless ? 'dictionary' : initialTab);
   $effect(() => {
-    if (vsAi) tab = 'dictionary';
+    if (chatless) tab = 'dictionary';
     else if (tab === 'dictionary' && !active) tab = 'chat';
   });
 </script>
@@ -43,7 +49,7 @@
 
   {#snippet tabbar()}
     <TabBar>
-      {#if !vsAi}
+      {#if !chatless}
         <button class="tab" class:active={tab === 'chat'} onclick={() => (tab = 'chat')}>
           <span class="face"><span class="sq" aria-hidden="true">💬</span><span class="lbl">{t('game.chat')}</span></span>
         </button>

ui/src/game/Game.svelte

@@ -4,24 +4,28 @@
   import TabBar from '../components/TabBar.svelte';
   import TapConfirm from '../components/TapConfirm.svelte';
   import Modal from '../components/Modal.svelte';
+  import PinPad from '../components/PinPad.svelte';
   import DictWarmup from '../components/DictWarmup.svelte';
   import Board from './Board.svelte';
   import Rack from './Rack.svelte';
   import { gateway } from '../lib/gateway';
+  import { gameSource, localSource, isLocalGameId } from '../lib/gamesource';
   import { notePreviewLocal, notePreviewNetwork } from '../lib/localeval-metrics';
   import { navigate } from '../lib/router.svelte';
   import { app, handleError, showToast, markChatRead, seedChatUnread } from '../lib/app.svelte';
   import { connection } from '../lib/connection.svelte';
+  import { offlineMode } from '../lib/offline.svelte';
   import { GatewayError } from '../lib/client';
   import { t, type MessageKey } from '../lib/i18n/index.svelte';
   import type { EvalResult, MoveRecord, MoveResult, StateView, Tile } from '../lib/model';
   import { lastMoveCells, replay } from '../lib/board';
   import { badgeKind } from '../lib/unread';
+  import { seatMedal } from '../lib/result';
   import { historyGrid } from '../lib/history';
   import { centre, premiumGrid } from '../lib/premiums';
   import { variantNameKey, usesStarBlank, BLANK_STAR } from '../lib/variants';
   import { alphabetLetters, hasAlphabet } from '../lib/alphabet';
-  import { hintsLeft } from '../lib/hints';
+  import { hintsLeft, hintGateRemainingMs, hintLockMinutes, HINT_GATE_MS } from '../lib/hints';
   import { downloadUrl, shareOrDownloadGcg, shareUrlAsFile } from '../lib/share';
   import { insideVK, vkAndroidWebView, vkCopyText, vkDownloadFile, vkPlatform, vkShowImages } from '../lib/vk';
   import { getCachedGame, setCachedGame, setCachedDraft, type CachedGame } from '../lib/gamecache';
@@ -47,6 +51,18 @@
 
   let { id }: { id: string } = $props();
 
+  // The game's source: the local engine for an offline game id, otherwise the network gateway. The
+  // screen calls the game-loop methods (state/history/submit/pass/exchange/resign/hint/evaluate/
+  // draft) through it, so the same UI drives a local vs_ai game and an online one alike.
+  const source = $derived(gameSource(id));
+  // A local (offline) game plays entirely on-device, so it is always ready; an online game needs a
+  // live connection — and offline mode's kill switch refuses its calls — so its network actions are
+  // disabled while disconnected or in offline mode (which also stops the "something went wrong"
+  // toasts a blocked call would otherwise raise).
+  const netReady = $derived(isLocalGameId(id) || (connection.online && !offlineMode.active));
+  // Unsubscribes from a local game's robot-reply events (offline only; null for a network game).
+  let localUnsub: (() => void) | null = null;
+
   let view = $state<StateView | null>(null);
   let moves = $state<MoveRecord[]>([]);
   let placement = $state<Placement>(newPlacement([]));
@@ -149,10 +165,42 @@
   const playable = $derived(!!view && (view.game.status === 'active' || view.game.status === 'open'));
   const isMyTurn = $derived(!!view && playable && view.game.toMove === view.seat);
   const gameOver = $derived(!!view && view.game.status === 'finished');
+  // Offline hotseat: the seat to move is PIN-locked until its owner enters the seat PIN this turn.
+  // While locked the board stays visible but the rack is withheld and the move controls disabled;
+  // canMove folds the lock into isMyTurn (locked is always false for a network / vs_ai game).
+  const locked = $derived(!!view?.locked);
+  const canMove = $derived(isMyTurn && !locked);
   // The hint badge: this game's allowance remaining plus the LIVE global wallet. Reading the
   // wallet from the profile (not the per-game view snapshot) keeps it correct after a wallet
   // hint was spent in another game (see lib/hints).
   const hintCount = $derived(hintsLeft(view, app.profile?.hintBalance ?? 0));
+  // A vs_ai game's hint is unlimited and wallet-free, but idle-gated (an anti-frustration aid: it
+  // unlocks only after the player has been stuck ~30 min on a turn). The source (the SERVER clock
+  // online, the device clock offline) tells us the SECONDS LEFT (view.hintUnlockLeftSeconds); we
+  // anchor a MONOTONIC countdown (performance.now()) to it, so a client clock change cannot skew it.
+  // A fresh value arrives on load (armHintGate below); when the robot moves the wait is the full
+  // window. `monoNow` ticks so the 🔒 lifts live at the mark.
+  let hintGateStart = $state<number | null>(null); // performance.now() at the last anchor; null = open
+  let gateLeftMs = $state(0);
+  let monoNow = $state(performance.now());
+  const hintRemaining = $derived(hintGateRemainingMs(hintGateStart, gateLeftMs, monoNow));
+  const hintGated = $derived(hintRemaining > 0);
+  // Anchor the countdown to a freshly received seconds-left (or open the gate). Called on every state
+  // load from the view, and on the robot's move to the full window (the robot just moved).
+  function armHintGate(leftSeconds: number): void {
+    if (leftSeconds > 0) {
+      hintGateStart = performance.now();
+      gateLeftMs = leftSeconds * 1000;
+    } else {
+      hintGateStart = null;
+      gateLeftMs = 0;
+    }
+  }
+  $effect(() => {
+    if (!view?.game.vsAi) return;
+    const iv = setInterval(() => (monoNow = performance.now()), 10_000);
+    return () => clearInterval(iv);
+  });
   // RACK_SIZE mirrors the engine's rules.RackSize (7 for every current variant). The exchange
   // gate is only a UX guard: the backend stays the source of truth and rejects an under-supplied
   // exchange regardless (engine rejects when bag.Len() < rules.RackSize).
@@ -190,11 +238,13 @@
       // Fetch the saved draft alongside state and history (best-effort) so the composition is
       // applied in the same tick the board appears — never as a second, visible rack→board step.
       const [st, hist, draft] = await Promise.all([
-        gateway.gameState(id, includeAlphabet),
+        source.gameState(id, includeAlphabet),
-        gateway.gameHistory(id),
+        source.gameHistory(id),
-        gateway.draftGet(id).catch(() => ''),
+        source.draftGet(id).catch(() => ''),
       ]);
       view = st;
+      // Anchor the vs_ai idle-hint countdown to the freshly fetched seconds-left (0 = open / non-vs_ai).
+      armHintGate(st.game.vsAi ? (st.hintUnlockLeftSeconds ?? 0) : 0);
       syncWallet(st.walletBalance);
       // Seed the unread flag from the authoritative state (the live stream only raises it).
       seedChatUnread(id, st.game.unreadChat, st.game.unreadMessages);
@@ -220,7 +270,7 @@
     setCachedDraft(id, json);
     if (draftSaveTimer) clearTimeout(draftSaveTimer);
     draftSaveTimer = setTimeout(() => {
-      void gateway.draftSave(id, json).catch(() => {});
+      void source.draftSave(id, json).catch(() => {});
     }, 500);
   }
   // applyDraft restores the player's saved composition over a freshly loaded state: the rack
@@ -247,6 +297,9 @@
     if (cached) {
       view = cached.view;
       moves = cached.moves;
+      // Arm the vs_ai idle-hint countdown from the cached seconds-left so the 🔒 shows at once on a
+      // warm open (no wait for load()); the cached value is a snapshot, refreshed by load() below.
+      armHintGate(cached.view.game.vsAi ? (cached.view.hintUnlockLeftSeconds ?? 0) : 0);
       // Apply the cached draft synchronously so a warm/preloaded open paints the pending tiles
       // already on the board (no full-rack-then-jump). load() then refreshes in the background.
       applyDraft(cached.view, cached.draft ?? '');
@@ -264,6 +317,12 @@
         dict = m;
       });
     }
+    // A local (offline) game has no live stream: route the source's robot-reply events through the
+    // same app event hub the network stream feeds, so the event effect above reacts to
+    // opponent_moved / game_over identically.
+    if (isLocalGameId(id)) {
+      localUnsub = localSource.events(id, (e) => (app.lastEvent = e));
+    }
   });
 
   // Warm the game's dictionary for the local move preview once, when both the game and the
@@ -309,7 +368,11 @@
         // While composing, reload so a draft overlapping the new move is reconciled; otherwise apply
         // the move as a delta with no fetch.
         if (placement.pending.length > 0) void load();
-        else applyDelta(applyMoveDelta(cacheSnapshot(), { move: e.move, game: e.game, bagLen: e.bagLen }));
+        else {
+          applyDelta(applyMoveDelta(cacheSnapshot(), { move: e.move, game: e.game, bagLen: e.bagLen }));
+          // The robot just moved (vs_ai) → the human's turn begins with the full idle window.
+          if (view?.game.vsAi) armHintGate(HINT_GATE_MS / 1000);
+        }
       } else if (e.kind === 'your_turn' && e.gameId === id) {
         // The opponent_moved delta carries the new state; your_turn only confirms the turn. Refetch
         // only if we missed the move (our cached count trails the event's).
@@ -611,8 +674,13 @@
     // Flush a pending draft save so leaving mid-composition still persists it.
     if (draftSaveTimer) {
       clearTimeout(draftSaveTimer);
-      void gateway.draftSave(id, serializeDraft(rackIds, placement.pending)).catch(() => {});
+      void source.draftSave(id, serializeDraft(rackIds, placement.pending)).catch(() => {});
     }
+    localUnsub?.();
+    // Leaving a hotseat game re-locks the current seat, so returning from the lobby re-prompts its
+    // PIN. Read the id from the loaded view, NOT the `id` prop: a $props() value reads back undefined
+    // during Svelte teardown, and isLocalGameId(undefined) would throw and abort this cleanup.
+    if (view?.game.hotseat) localSource.relock(view.game.id);
   });
 
   function onCell(row: number, col: number) {
@@ -717,8 +785,8 @@
     // rapid placements do not pile up requests on a slow link.
     evalCtrl?.abort();
     evalCtrl = null;
-    // Off-turn the composition is position-only: no score preview or evaluate.
+    // Off-turn (or a locked hotseat seat) the composition is position-only: no score preview.
-    if (!isMyTurn) return;
+    if (!canMove) return;
     const sub = toSubmit(placement);
     if (!sub) return;
     // Instant on-device preview when the game's dictionary is warm; the network otherwise.
@@ -740,7 +808,7 @@
     evalCtrl = ctrl;
     previewTimer = setTimeout(async () => {
       try {
-        preview = await gateway.evaluate(id, sub.tiles, variant, ctrl.signal);
+        preview = await source.evaluate(id, sub.tiles, variant, ctrl.signal);
         notePreviewNetwork();
       } catch {
         /* best-effort (or aborted) */
@@ -776,12 +844,106 @@
     refreshRecent();
   }
 
+  // --- offline hotseat: seat unlock + host (referee) overrides -------------------
+  let unlockOpen = $state(false); // the current locked seat's owner enters their PIN to reveal the rack
+  // The host menu: 'pin' collects the master PIN, then 'menu' lists the overrides. hostPinEntered is
+  // the verified master PIN, reused to authorise the chosen action (the source re-checks it).
+  let hostMenuStep = $state<'closed' | 'pin' | 'menu'>('closed');
+  let hostPinEntered = $state('');
+  // The pending host action awaiting its confirm ("Skip X's turn?" etc.); null shows the menu list.
+  let hostConfirm = $state<{ action: 'skip' | 'resign' | 'terminate'; seat?: number; name?: string } | null>(null);
+  let hostDone = $state(false); // the transient success ✅ shown after an override
+
+  // hotseatName is the plain display name of a seat by index (hotseat seats are account-less local
+  // players, so no "you"/🤖 resolution is needed — unlike the seat-object seatName used elsewhere).
+  function hotseatName(i: number): string {
+    return view?.game.seats[i]?.displayName ?? '';
+  }
+
+  function startSkip(): void {
+    if (!view) return;
+    hostConfirm = { action: 'skip', seat: view.game.toMove, name: hotseatName(view.game.toMove) };
+  }
+
+  function flashDone(): void {
+    hostDone = true;
+    setTimeout(() => (hostDone = false), 1100);
+  }
+
+  // advanceHotseat re-points the screen at the next seat after a hotseat move: the source has advanced
+  // the turn and re-locked, so a fresh state gives the next seat's rack (empty while it is locked).
+  async function advanceHotseat(): Promise<void> {
+    const st = await source.gameState(id, false);
+    view = st;
+    rackIds = st.rack.map((_, i) => i);
+    placement = newPlacement(st.rack);
+    selected = null;
+    preview = null;
+    setCachedGame(id, st, moves, '');
+  }
+
+  // onUnlock verifies the current seat's PIN through the source (which reveals the rack on success)
+  // and applies the unlocked state; handed to the PIN pad as its verifier.
+  async function onUnlock(pin: string): Promise<boolean> {
+    try {
+      const st = await localSource.unlockSeat(id, pin);
+      view = st;
+      rackIds = st.rack.map((_, i) => i);
+      placement = newPlacement(st.rack);
+      selected = null;
+      return true;
+    } catch {
+      return false;
+    }
+  }
+
+  // verifyHost captures the entered master PIN (reused to authorise the chosen action) and checks it.
+  async function verifyHost(pin: string): Promise<boolean> {
+    hostPinEntered = pin;
+    return localSource.verifyHostPin(id, pin);
+  }
+
+  function hostConfirmText(c: { action: 'skip' | 'resign' | 'terminate'; name?: string }): string {
+    if (c.action === 'skip') return t('hotseat.askSkip', { name: c.name ?? '' });
+    if (c.action === 'resign') return t('hotseat.askExclude', { name: c.name ?? '' });
+    return t('hotseat.askTerminate');
+  }
+
+  async function runHostAction(): Promise<void> {
+    if (!hostConfirm) return;
+    const { action, seat } = hostConfirm;
+    hostConfirm = null;
+    hostMenuStep = 'closed';
+    busy = true;
+    try {
+      const st = await localSource.hostAction(id, hostPinEntered, action, seat);
+      if (st === null) {
+        navigate('/'); // terminated: the game is deleted, so return to the lobby
+        return;
+      }
+      view = st;
+      rackIds = st.rack.map((_, i) => i);
+      placement = newPlacement(st.rack);
+      selected = null;
+      preview = null;
+      moves = (await source.gameHistory(id)).moves; // a skip / resign added a journal move
+      setCachedGame(id, st, moves, '');
+      flashDone();
+    } catch (e) {
+      handleError(e);
+    } finally {
+      busy = false;
+      hostPinEntered = '';
+    }
+  }
+
   async function commit() {
     const sub = toSubmit(placement);
     if (!sub) return;
     busy = true;
     try {
-      applyMoveResult(await gateway.submitPlay(id, sub.tiles, variant));
+      applyMoveResult(await source.submitPlay(id, sub.tiles, variant));
+      if (view?.game.hotseat) await advanceHotseat();
       haptic('success');
       zoomed = false;
     } catch (e) {
@@ -800,7 +962,8 @@
   async function doPass() {
     busy = true;
     try {
-      applyMoveResult(await gateway.pass(id));
+      applyMoveResult(await source.pass(id));
+      if (view?.game.hotseat) await advanceHotseat();
     } catch (e) {
       handleError(e);
     } finally {
@@ -821,7 +984,7 @@
     resignOpen = false;
     busy = true;
     try {
-      applyMoveResult(await gateway.resign(id));
+      applyMoveResult(await source.resign(id));
       // Reveal the final board once the game is resigned: close the move-history drawer
       // (portrait — the landscape dock is unaffected) and zoom out if it was magnified.
       historyOpen = false;
@@ -833,8 +996,17 @@
     }
   }
   async function doHint() {
+    // vs_ai: the idle gate replaces the wallet. While it is still closed, a tap only explains when the
+    // hint unlocks (no wallet is ever spent) — matching the 🔒 badge. Measured fresh at tap time.
+    if (view?.game.vsAi) {
+      const remaining = hintGateRemainingMs(hintGateStart, gateLeftMs, performance.now());
+      if (remaining > 0) {
+        showToast(t('game.hintLockedIn', { n: hintLockMinutes(remaining) }), 'info');
+        return;
+      }
+    }
     try {
-      const h = await gateway.hint(id);
+      const h = await source.hint(id);
       if (h.move.tiles.length && view) {
         placement = placementFromHint(h.move.tiles, view.rack);
         // Scroll the (zoomed) board to the hint's placement rather than the top-left:
@@ -869,6 +1041,12 @@
       // The backend does not spend a hint when there is no move.
       if (e instanceof GatewayError && e.code === 'no_hint_available') {
         showToast(t('game.noHintOptions'), 'info');
+      } else if (e instanceof GatewayError && e.code === 'hint_locked') {
+        // The server-clock backstop refused a vs_ai hint the client thought was open (a rare client
+        // clock desync): re-sync the countdown from a fresh fetch and explain the gate.
+        await load();
+        const left = hintGateRemainingMs(hintGateStart, gateLeftMs, performance.now());
+        showToast(t('game.hintLockedIn', { n: hintLockMinutes(left || 60_000) }), 'info');
       } else {
         handleError(e);
       }
@@ -906,7 +1084,8 @@
     exchangeOpen = false;
     busy = true;
     try {
-      applyMoveResult(await gateway.exchange(id, tiles, variant));
+      applyMoveResult(await source.exchange(id, tiles, variant));
+      if (view?.game.hotseat) await advanceHotseat();
     } catch (e) {
       handleError(e);
     } finally {
@@ -928,7 +1107,15 @@
     if (!view) return '';
     const me = view.game.seats[view.seat];
     if (me?.isWinner) return t('game.won');
-    return view.game.seats.some((s) => s.isWinner) ? t('game.lost') : t('game.tied');
+    if (view.game.endReason === 'aborted') return t('game.tied'); // an abort is a draw for everyone
+    const myScore = me?.score ?? 0;
+    // A declared winner (incl. by resignation) that is not me, or anyone who scored higher → a loss.
+    if (view.game.seats.some((s) => s.isWinner) || view.game.seats.some((s) => !s.resigned && s.score > myScore)) {
+      return t('game.lost');
+    }
+    // No one above me and no declared winner: a tie for the lead is a (shared) win; only an
+    // all-level finish is a draw.
+    return view.game.seats.filter((s) => !s.resigned).every((s) => s.score === myScore) ? t('game.tied') : t('game.won');
   }
 
   // The finished-game export offers two formats — the GCG file and the server-rendered PNG
@@ -1244,8 +1431,9 @@
   // (not the still-empty seat of an open game) who is not yet a friend (an already-requested
   // opponent still shows it, but disabled).
   function canAddFriend(s: { accountId: string; seat: number }): boolean {
-    // Never offer add-friend against an AI opponent, an existing friend, or a blocked player.
+    // Never offer add-friend against an AI opponent, an existing friend, or a blocked player — nor in
-    if (view?.game.vsAi) return false;
+    // a local (offline) game, whose seats are account-less: vs_ai, and hotseat's synthetic seat ids.
+    if (view?.game.vsAi || isLocalGameId(id)) return false;
     return (
       !!s.accountId &&
       !app.profile?.isGuest &&
@@ -1259,7 +1447,7 @@
   // may still be blocked (the block overrides the friendship), so it omits the friend exclusion.
   // An already-blocked opponent hides it (both controls go, and the name is struck).
   function canBlock(s: { accountId: string; seat: number }): boolean {
-    if (view?.game.vsAi) return false;
+    if (view?.game.vsAi || isLocalGameId(id)) return false;
     return !!s.accountId && !app.profile?.isGuest && s.accountId !== app.session?.userId && !seatBlocked(s);
   }
 </script>
@@ -1317,7 +1505,7 @@
       {#if badge}<span class="unread-dot sbadge-dot" class:nudge={badge === 'nudge'}></span>{/if}
       {#each view.game.seats as s (s.seat)}
         <div class="seat" class:turn={view.game.toMove === s.seat && !gameOver} class:win={s.isWinner}>
-          <div class="nm" class:struck={seatBlocked(s)}>{seatName(s)}</div>
+          <div class="nm" class:struck={seatBlocked(s)}>{#if gameOver && view.game.hotseat}<span class="medal" aria-hidden="true">{seatMedal(view.game, s.seat)}</span>{/if}{seatName(s)}</div>
           <div class="sc" class:blockprompt={blockConfirm[s.seat]}>
             {#if blockConfirm[s.seat]}{t('game.blockShort')}{:else if addConfirm[s.seat]}{t('game.addFriendShort')}{:else}{s.score}{/if}
           </div>
@@ -1361,13 +1549,18 @@
         {:else}
           <button class="hicon" onclick={onExportClick} aria-label={t('game.exportGcg')}>📤</button>
         {/if}
+      {:else if view.game.hotseat}
+        <!-- Hotseat resign is a host (referee) action, not self-serve; keep the slot empty. -->
+        <span aria-hidden="true"></span>
       {:else}
         <button class="hicon" onclick={onResignClick} disabled={waitingForOpponent} aria-label={t('game.dropGame')}>🏁</button>
       {/if}
       {#if !view.game.multipleWordsPerTurn}<span class="oneword-label">{t('game.oneWordRule')}</span>{/if}
-      <!-- A finished AI game has no comms at all (no chat, and the dictionary closes with the
+      <!-- The comms entry opens Chat + the word Dictionary. A local game (vs_ai or hotseat) has no
-           game), so the entry is dropped; an active AI game keeps it (it opens the dictionary). -->
+           chat, so its hub is Dictionary-only (CommsHub), and once finished the dictionary closes too
-      {#if !(gameOver && view.game.vsAi)}
+           — so drop the entry only when a local game is finished; an active local game keeps it for
+           the Dictionary. An online game always keeps it (chat outlives the game). -->
+      {#if !(gameOver && (view.game.vsAi || view.game.hotseat))}
         <button class="hicon" onclick={() => navigate(`/game/${id}/chat`)} aria-label={t('game.chat')}>
           {#key chatBlink}<span class="chat-ico" class:blink={chatBlink > 0 && !app.reduceMotion}>💬</span>{/key}
         </button>
@@ -1438,9 +1631,12 @@
     <div class="status">
       <span>{view.bagLen === 0 ? t('game.bagEmpty') : t('game.bag', { n: view.bagLen })}</span>
       {#if gameOver}
-        <strong class="over">{resultText()}</strong>
+        <!-- A hotseat game shows its result as per-seat medals on the plaques (below), not a
+             viewer-centric "you won/lost" — with 2-4 local players there is no single "you". A vs_ai
+             game keeps the "you won/lost" text (one human). -->
+        {#if !view.game.hotseat}<strong class="over">{resultText()}</strong>{/if}
       {:else if placement.pending.length === 0}
-        <span class="turn-ind">{isMyTurn ? t('game.yourTurn') : turnLabel()}</span>
+        <span class="turn-ind">{view.game.hotseat ? t('hotseat.turnOf', { name: hotseatName(view.game.toMove) }) : isMyTurn ? t('game.yourTurn') : turnLabel()}</span>
       {/if}
       <span class="scores">
         {#if recallOverRack}{:else if preview}{preview.legal ? t('game.previewWords', { words: preview.words.join(', '), n: preview.score }) : t('game.previewIllegal')}{/if}
@@ -1454,36 +1650,58 @@
        a finished game shows the final rack greyed out and the controls disabled. -->
   <div class="rack-row" class:inert={gameOver} data-coach="game-rack">
     <div class="rack-wrap">
-      <Rack
+      {#if locked}
-        slots={rackSlots}
+        <!-- A PIN-locked hotseat seat: the rack is withheld until its owner unlocks it. The board
-        {variant}
+             above stays visible; only this tray is gated. -->
-        {selected}
+        <button class="unlock" onclick={() => (unlockOpen = true)}>🔒 {t('hotseat.unlock')}</button>
-        {landscape}
+      {:else}
-        shuffling={shuffling && !app.reduceMotion}
+        <Rack
-        draggingId={reorderDragId}
+          slots={rackSlots}
-        dropIndex={reorderTo}
+          {variant}
-        ondown={onRackDown}
+          {selected}
-      />
+          {landscape}
+          shuffling={shuffling && !app.reduceMotion}
+          draggingId={reorderDragId}
+          dropIndex={reorderTo}
+          ondown={onRackDown}
+        />
+      {/if}
     </div>
     {#if !gameOver && placement.pending.length > 0 && !recallOverRack}
-      <button class="make" onclick={commit} disabled={busy || !isMyTurn || !connection.online || !preview?.legal} aria-label={t('game.makeMove')}>✅</button>
+      <button class="make" onclick={commit} disabled={busy || !canMove || !netReady || !preview?.legal} aria-label={t('game.makeMove')}>✅</button>
     {/if}
   </div>
 {/snippet}
 
 {#snippet controlButtons()}
-  <button class="tab" disabled={busy || !isMyTurn || !connection.online} onclick={openExchange}>
+  <button class="tab" disabled={busy || !canMove || !netReady} onclick={openExchange}>
     <span class="sq" data-coach="game-turn">🔄</span><span class="lbl">{t('game.draw')}</span>
   </button>
-  <TapConfirm
+  {#if view?.game.hotseat}
-    triggerClass="tab"
+    <!-- Hotseat: no hints. The freed slot becomes the host (referee) button — always available
-    label={t('game.hint')}
+         (even on a locked seat: the host may skip a player who forgot their PIN). -->
-    disabled={busy || !isMyTurn || !connection.online || hintCount <= 0}
+    <button class="tab" disabled={busy || gameOver} onclick={() => (hostMenuStep = 'pin')}>
-    onconfirm={doHint}
+      <span class="sq">🔐</span><span class="lbl">{t('hotseat.host')}</span>
-  >
+    </button>
-    <span class="sq" data-coach="game-hints">🛟{#if hintCount > 0}<span class="badge">{hintCount}</span>{/if}</span>
+  {:else if view?.game.vsAi}
-    <span class="lbl">{t('game.hint')}</span>
+    <!-- vs_ai hints are unlimited and wallet-free, so no confirm and no count. A 🔒 badge marks the
-  </TapConfirm>
+         idle gate while it is closed; tapping then only explains when it opens (doHint), and the lock
+         lifts live at the unlock moment. -->
+    <button class="tab" disabled={busy || !isMyTurn || !netReady} onclick={doHint}>
+      <span class="sq" data-coach="game-hints">🛟{#if hintGated}<span class="lock" aria-hidden="true">🔒</span>{/if}</span>
+      <span class="lbl">{t('game.hint')}</span>
+    </button>
+  {:else}
+    <TapConfirm
+      triggerClass="tab"
+      label={t('game.hint')}
+      disabled={busy || !isMyTurn || !netReady || hintCount <= 0}
+      onconfirm={doHint}
+    >
+      <span class="sq" data-coach="game-hints">🛟{#if hintCount > 0}<span class="badge">{hintCount}</span>{/if}</span>
+      <span class="lbl">{t('game.hint')}</span>
+    </TapConfirm>
+  {/if}
   {#if placement.pending.length > 0}
     <button class="tab" disabled={busy} onclick={resetPlacement}>
       <span class="sq">↩️</span><span class="lbl">{t('game.reset')}</span>
@@ -1536,11 +1754,60 @@
   <Modal title={t('game.confirmResign')} onclose={() => (resignOpen = false)}>
     <div class="confirm-row">
       <button class="cancel" onclick={() => (resignOpen = false)}>{t('common.cancel')}</button>
-      <button class="danger" onclick={doResign} disabled={!connection.online}>{t('game.dropGame')}</button>
+      <button class="danger" onclick={doResign} disabled={!netReady}>{t('game.dropGame')}</button>
     </div>
   </Modal>
 {/if}
 
+<!-- Offline hotseat: unlock the current seat's rack. -->
+{#if unlockOpen && view}
+  <PinPad
+    mode="verify"
+    title={t('hotseat.unlockTitle', { name: hotseatName(view.game.toMove) })}
+    verify={onUnlock}
+    onclose={() => (unlockOpen = false)}
+    onresult={() => (unlockOpen = false)}
+  />
+{/if}
+
+<!-- Offline hotseat: the host (referee) enters the master PIN, then picks an override. -->
+{#if hostMenuStep === 'pin'}
+  <PinPad
+    mode="verify"
+    title={t('hotseat.host')}
+    verify={verifyHost}
+    onclose={() => (hostMenuStep = 'closed')}
+    onresult={() => (hostMenuStep = 'menu')}
+  />
+{/if}
+{#if hostMenuStep === 'menu' && view}
+  <Modal title={t('hotseat.host')} onclose={() => { hostMenuStep = 'closed'; hostConfirm = null; }}>
+    {#if hostConfirm}
+      <p class="host-q">{hostConfirmText(hostConfirm)}</p>
+      <div class="confirm-row">
+        <button class="cancel" onclick={() => (hostConfirm = null)}>{t('common.cancel')}</button>
+        <button class="danger" onclick={runHostAction}>{t('common.ok')}</button>
+      </div>
+    {:else}
+      <div class="host-menu">
+        <button class="host-act" onclick={startSkip}>
+          {t('hotseat.skip')}
+        </button>
+        <div class="host-sub">{t('hotseat.exclude')}</div>
+        {#each view.game.seats as s (s.seat)}
+          <button class="host-seat" onclick={() => (hostConfirm = { action: 'resign', seat: s.seat, name: s.displayName })}>
+            {s.displayName}
+          </button>
+        {/each}
+        <button class="host-act danger" onclick={() => (hostConfirm = { action: 'terminate' })}>{t('hotseat.terminate')}</button>
+      </div>
+    {/if}
+  </Modal>
+{/if}
+{#if hostDone}
+  <div class="host-done" aria-hidden="true">✅</div>
+{/if}
+
 {#if exportOpen}
   <Modal title={t('game.exportGcg')} onclose={() => (exportOpen = false)}>
     <div class="export-opts">
@@ -1548,7 +1815,7 @@
         <button
           class="confirm"
           onclick={() => { exportOpen = false; void exportArtifact('png'); }}
-          disabled={!connection.online}
+          disabled={!netReady}
         >
           {t('game.exportImageOpt')}
         </button>
@@ -1556,7 +1823,7 @@
       <button
         class={exportImageAvailable ? 'export-alt' : 'confirm'}
         onclick={() => { exportOpen = false; void exportArtifact('gcg'); }}
-        disabled={!connection.online}
+        disabled={!netReady}
       >
         {t('game.exportGcgOpt')}
       </button>
@@ -1610,6 +1877,10 @@
     overflow: hidden;
     text-overflow: ellipsis;
   }
+  /* The finished-game place medal on a local (offline) seat plaque, left of the name. */
+  .medal {
+    margin-right: 3px;
+  }
   .sc {
     font-weight: 700;
     font-variant-numeric: tabular-nums;
@@ -2031,4 +2302,76 @@
   .scoreboard.flat {
     cursor: default;
   }
+  /* The vs_ai hint's idle lock: a small 🔒 at the icon-square corner (the .sq is positioned by the
+     shared TabBar rule). No count pill — the hint is unlimited; the lock alone marks the gate. */
+  .sq .lock {
+    position: absolute;
+    top: -4px;
+    right: -4px;
+    font-size: 0.62rem;
+    line-height: 1;
+  }
+  /* --- offline hotseat --- */
+  /* The locked-seat rack overlay: fills the rack tray with an "unlock" button, the board above
+     stays visible. */
+  .unlock {
+    width: 100%;
+    height: 100%;
+    min-height: 44px;
+    border: 1px dashed var(--border);
+    border-radius: var(--radius-sm);
+    background: var(--surface);
+    color: var(--text);
+    font-weight: 600;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    gap: 8px;
+  }
+  .host-menu {
+    display: flex;
+    flex-direction: column;
+    gap: 8px;
+  }
+  .host-act,
+  .host-seat {
+    padding: 12px;
+    border: 1px solid var(--border);
+    border-radius: var(--radius-sm);
+    background: var(--surface);
+    color: var(--text);
+    font-weight: 600;
+    text-align: left;
+  }
+  .host-act.danger {
+    border-color: var(--danger);
+    color: var(--danger);
+  }
+  .host-sub {
+    font-size: 0.8rem;
+    color: var(--text-muted);
+    margin-top: 4px;
+  }
+  .host-q {
+    margin: 0 0 12px;
+    font-weight: 600;
+  }
+  /* The transient success tick after a host override — a centred ✅ that fades out on a timer. */
+  .host-done {
+    position: fixed;
+    inset: 0;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    font-size: 4rem;
+    z-index: 50;
+    pointer-events: none;
+    animation: host-done-fade 1.1s ease forwards;
+  }
+  @keyframes host-done-fade {
+    0% { opacity: 0; transform: scale(0.7); }
+    25% { opacity: 1; transform: scale(1); }
+    75% { opacity: 1; transform: scale(1); }
+    100% { opacity: 0; transform: scale(1); }
+  }
 </style>

ui/src/gen/fbs/scrabblefb.ts

@@ -17,6 +17,7 @@ export { ChatPostRequest } from './scrabblefb/chat-post-request.js';
 export { CheckWordRequest } from './scrabblefb/check-word-request.js';
 export { ComplaintRequest } from './scrabblefb/complaint-request.js';
 export { CreateInvitationRequest } from './scrabblefb/create-invitation-request.js';
+export { DictVersion } from './scrabblefb/dict-version.js';
 export { DraftRequest } from './scrabblefb/draft-request.js';
 export { DraftView } from './scrabblefb/draft-view.js';
 export { EmailConfirmLinkRequest } from './scrabblefb/email-confirm-link-request.js';

ui/src/gen/fbs/scrabblefb/dict-version.ts

@@ -0,0 +1,60 @@
+// automatically generated by the FlatBuffers compiler, do not modify
+
+import * as flatbuffers from 'flatbuffers';
+
+export class DictVersion {
+  bb: flatbuffers.ByteBuffer|null = null;
+  bb_pos = 0;
+  __init(i:number, bb:flatbuffers.ByteBuffer):DictVersion {
+  this.bb_pos = i;
+  this.bb = bb;
+  return this;
+}
+
+static getRootAsDictVersion(bb:flatbuffers.ByteBuffer, obj?:DictVersion):DictVersion {
+  return (obj || new DictVersion()).__init(bb.readInt32(bb.position()) + bb.position(), bb);
+}
+
+static getSizePrefixedRootAsDictVersion(bb:flatbuffers.ByteBuffer, obj?:DictVersion):DictVersion {
+  bb.setPosition(bb.position() + flatbuffers.SIZE_PREFIX_LENGTH);
+  return (obj || new DictVersion()).__init(bb.readInt32(bb.position()) + bb.position(), bb);
+}
+
+variant():string|null
+variant(optionalEncoding:flatbuffers.Encoding):string|Uint8Array|null
+variant(optionalEncoding?:any):string|Uint8Array|null {
+  const offset = this.bb!.__offset(this.bb_pos, 4);
+  return offset ? this.bb!.__string(this.bb_pos + offset, optionalEncoding) : null;
+}
+
+version():string|null
+version(optionalEncoding:flatbuffers.Encoding):string|Uint8Array|null
+version(optionalEncoding?:any):string|Uint8Array|null {
+  const offset = this.bb!.__offset(this.bb_pos, 6);
+  return offset ? this.bb!.__string(this.bb_pos + offset, optionalEncoding) : null;
+}
+
+static startDictVersion(builder:flatbuffers.Builder) {
+  builder.startObject(2);
+}
+
+static addVariant(builder:flatbuffers.Builder, variantOffset:flatbuffers.Offset) {
+  builder.addFieldOffset(0, variantOffset, 0);
+}
+
+static addVersion(builder:flatbuffers.Builder, versionOffset:flatbuffers.Offset) {
+  builder.addFieldOffset(1, versionOffset, 0);
+}
+
+static endDictVersion(builder:flatbuffers.Builder):flatbuffers.Offset {
+  const offset = builder.endObject();
+  return offset;
+}
+
+static createDictVersion(builder:flatbuffers.Builder, variantOffset:flatbuffers.Offset, versionOffset:flatbuffers.Offset):flatbuffers.Offset {
+  DictVersion.startDictVersion(builder);
+  DictVersion.addVariant(builder, variantOffset);
+  DictVersion.addVersion(builder, versionOffset);
+  return DictVersion.endDictVersion(builder);
+}
+}

ui/src/gen/fbs/scrabblefb/email-request-request.ts

@@ -41,8 +41,13 @@ language(optionalEncoding?:any):string|Uint8Array|null {
   return offset ? this.bb!.__string(this.bb_pos + offset, optionalEncoding) : null;
 }
 
+pwa():boolean {
+  const offset = this.bb!.__offset(this.bb_pos, 10);
+  return offset ? !!this.bb!.readInt8(this.bb_pos + offset) : false;
+}
+
 static startEmailRequestRequest(builder:flatbuffers.Builder) {
-  builder.startObject(3);
+  builder.startObject(4);
 }
 
 static addEmail(builder:flatbuffers.Builder, emailOffset:flatbuffers.Offset) {
@@ -57,16 +62,21 @@ static addLanguage(builder:flatbuffers.Builder, languageOffset:flatbuffers.Offse
   builder.addFieldOffset(2, languageOffset, 0);
 }
 
+static addPwa(builder:flatbuffers.Builder, pwa:boolean) {
+  builder.addFieldInt8(3, +pwa, +false);
+}
+
 static endEmailRequestRequest(builder:flatbuffers.Builder):flatbuffers.Offset {
   const offset = builder.endObject();
   return offset;
 }
 
-static createEmailRequestRequest(builder:flatbuffers.Builder, emailOffset:flatbuffers.Offset, browserTzOffset:flatbuffers.Offset, languageOffset:flatbuffers.Offset):flatbuffers.Offset {
+static createEmailRequestRequest(builder:flatbuffers.Builder, emailOffset:flatbuffers.Offset, browserTzOffset:flatbuffers.Offset, languageOffset:flatbuffers.Offset, pwa:boolean):flatbuffers.Offset {
   EmailRequestRequest.startEmailRequestRequest(builder);
   EmailRequestRequest.addEmail(builder, emailOffset);
   EmailRequestRequest.addBrowserTz(builder, browserTzOffset);
   EmailRequestRequest.addLanguage(builder, languageOffset);
+  EmailRequestRequest.addPwa(builder, pwa);
   return EmailRequestRequest.endEmailRequestRequest(builder);
 }
 }

ui/src/gen/fbs/scrabblefb/profile.ts

@@ -3,6 +3,7 @@
 import * as flatbuffers from 'flatbuffers';
 
 import { BannerInfo } from '../scrabblefb/banner-info.js';
+import { DictVersion } from '../scrabblefb/dict-version.js';
 
 
 export class Profile {
@@ -124,8 +125,18 @@ vkLinked():boolean {
   return offset ? !!this.bb!.readInt8(this.bb_pos + offset) : false;
 }
 
+dictVersions(index: number, obj?:DictVersion):DictVersion|null {
+  const offset = this.bb!.__offset(this.bb_pos, 36);
+  return offset ? (obj || new DictVersion()).__init(this.bb!.__indirect(this.bb!.__vector(this.bb_pos + offset) + index * 4), this.bb!) : null;
+}
+
+dictVersionsLength():number {
+  const offset = this.bb!.__offset(this.bb_pos, 36);
+  return offset ? this.bb!.__vector_len(this.bb_pos + offset) : 0;
+}
+
 static startProfile(builder:flatbuffers.Builder) {
-  builder.startObject(16);
+  builder.startObject(17);
 }
 
 static addUserId(builder:flatbuffers.Builder, userIdOffset:flatbuffers.Offset) {
@@ -204,6 +215,22 @@ static addVkLinked(builder:flatbuffers.Builder, vkLinked:boolean) {
   builder.addFieldInt8(15, +vkLinked, +false);
 }
 
+static addDictVersions(builder:flatbuffers.Builder, dictVersionsOffset:flatbuffers.Offset) {
+  builder.addFieldOffset(16, dictVersionsOffset, 0);
+}
+
+static createDictVersionsVector(builder:flatbuffers.Builder, data:flatbuffers.Offset[]):flatbuffers.Offset {
+  builder.startVector(4, data.length, 4);
+  for (let i = data.length - 1; i >= 0; i--) {
+    builder.addOffset(data[i]!);
+  }
+  return builder.endVector();
+}
+
+static startDictVersionsVector(builder:flatbuffers.Builder, numElems:number) {
+  builder.startVector(4, numElems, 4);
+}
+
 static endProfile(builder:flatbuffers.Builder):flatbuffers.Offset {
   const offset = builder.endObject();
   return offset;

ui/src/gen/fbs/scrabblefb/state-view.ts

@@ -74,8 +74,13 @@ walletBalance():number {
   return offset ? this.bb!.readInt32(this.bb_pos + offset) : 0;
 }
 
+hintUnlockLeftSeconds():number {
+  const offset = this.bb!.__offset(this.bb_pos, 18);
+  return offset ? this.bb!.readInt32(this.bb_pos + offset) : 0;
+}
+
 static startStateView(builder:flatbuffers.Builder) {
-  builder.startObject(7);
+  builder.startObject(8);
 }
 
 static addGame(builder:flatbuffers.Builder, gameOffset:flatbuffers.Offset) {
@@ -130,12 +135,16 @@ static addWalletBalance(builder:flatbuffers.Builder, walletBalance:number) {
   builder.addFieldInt32(6, walletBalance, 0);
 }
 
+static addHintUnlockLeftSeconds(builder:flatbuffers.Builder, hintUnlockLeftSeconds:number) {
+  builder.addFieldInt32(7, hintUnlockLeftSeconds, 0);
+}
+
 static endStateView(builder:flatbuffers.Builder):flatbuffers.Offset {
   const offset = builder.endObject();
   return offset;
 }
 
-static createStateView(builder:flatbuffers.Builder, gameOffset:flatbuffers.Offset, seat:number, rackOffset:flatbuffers.Offset, bagLen:number, hintsRemaining:number, alphabetOffset:flatbuffers.Offset, walletBalance:number):flatbuffers.Offset {
+static createStateView(builder:flatbuffers.Builder, gameOffset:flatbuffers.Offset, seat:number, rackOffset:flatbuffers.Offset, bagLen:number, hintsRemaining:number, alphabetOffset:flatbuffers.Offset, walletBalance:number, hintUnlockLeftSeconds:number):flatbuffers.Offset {
   StateView.startStateView(builder);
   StateView.addGame(builder, gameOffset);
   StateView.addSeat(builder, seat);
@@ -144,6 +153,7 @@ static createStateView(builder:flatbuffers.Builder, gameOffset:flatbuffers.Offse
   StateView.addHintsRemaining(builder, hintsRemaining);
   StateView.addAlphabet(builder, alphabetOffset);
   StateView.addWalletBalance(builder, walletBalance);
+  StateView.addHintUnlockLeftSeconds(builder, hintUnlockLeftSeconds);
   return StateView.endStateView(builder);
 }
 }

ui/src/lib/app.svelte.ts

@@ -35,12 +35,17 @@ import {
 } from './telegram';
 import { onVKPath, insideVK, vkInit, vkClose, vkDisableSwipeBack, vkLaunchParams, vkUserName, vkStartParam, vkOnScheme, vkOnInsets, vkSetViewSettings, appearanceForBg } from './vk';
 import { pendingVKLink, type VKLinkCallback } from './vkid';
+import { isStandalone } from './pwa';
+import { registerServiceWorker } from './pwa.svelte';
 import { haptic } from './haptics';
 import { CLOUD_PREFS_KEY, decodeClientPrefs, encodeClientPrefs } from './cloudprefs';
 import { parseStartParam } from './deeplink';
 import {
   clearOnboarding,
   clearSession,
+  clearProfile,
+  loadProfile,
+  saveProfile,
   loadOnboarding,
   loadPrefs,
   loadSession,
@@ -50,7 +55,9 @@ import {
   savePrefs,
 } from './session';
 import type { CoachSeries } from './coachmark';
-import { connection, reportOffline, reportOnline, resetConnection } from './connection.svelte';
+import { connection, reportOffline, reportOnline, resetConnection, checkReachable } from './connection.svelte';
+import { offlineMode, setOfflineMode } from './offline.svelte';
+import { shouldBootOffline } from './offline';
 import { isConnectionCode } from './retry';
 import { clearGameCache, getCachedGame, setCachedGame } from './gamecache';
 import { advanceCached } from './gamedelta';
@@ -71,6 +78,10 @@ export const app = $state<{
    *  backend was down during a deploy). App.svelte then renders the boot-error retry screen
    *  instead of the web login — a Mini App has no manual sign-in to fall back to. */
   bootError: boolean;
+  /** True while the cold-start "no connection — go offline?" dialog is up (the reachability check
+   *  timed out with the network interface reportedly online). App.svelte renders it over the splash;
+   *  bootstrap awaits the choice via resolveOfflinePrompt. */
+  offlinePrompt: boolean;
   /** On the dedicated /telegram/ entry, set to a privacy-safe diagnostic snapshot when a Mini App
    *  launch carried no sign-in data (empty initData). App.svelte then renders the compact
    *  launch-error screen (screens/TelegramLaunchError) — a shareable probe for why Telegram
@@ -141,6 +152,7 @@ export const app = $state<{
 }>({
   ready: false,
   bootError: false,
+  offlinePrompt: false,
   launchError: null,
   debugOpen: false,
   lobbyReady: false,
@@ -292,7 +304,9 @@ export function handleError(err: unknown): void {
     void enterBlocked();
     return;
   }
-  if (isConnectionCode(code) || !connection.online) return;
+  // A blocked call in offline mode ('offline', the transport kill switch) is expected, not an error
+  // to surface — the offline chrome already signals the state; never a red toast.
+  if (isConnectionCode(code) || code === 'offline' || !connection.online) return;
   haptic('error');
   showToast(t(code ? errorKey(code) : 'error.generic'), 'error');
 }
@@ -458,6 +472,7 @@ export async function refreshProfile(): Promise<void> {
   if (!app.session) return;
   try {
     app.profile = await gateway.profileGet();
+    void saveProfile($state.snapshot(app.profile)); // keep the offline-boot cache fresh (plain snapshot)
   } catch {
     // Best-effort; the banner just stays as it was until the next fetch.
   }
@@ -515,6 +530,11 @@ async function adoptSession(s: Session): Promise<void> {
   await saveSession(s);
   try {
     app.profile = await gateway.profileGet();
+    // Persist the profile so a later offline cold start can launch from it (its variant
+    // preferences, dictionary versions and display name) without a network fetch. Snapshot to a
+    // plain object first — the reactive $state proxy is not structured-cloneable, so it would fail
+    // the IndexedDB write and fall back to a localStorage entry that loadProfile never reads.
+    void saveProfile($state.snapshot(app.profile));
     // The live interface language follows the device — the explicit local choice (saved in
     // prefs) or the system guess made at bootstrap — and is no longer overridden from the
     // account here: the Telegram bot a user signs in through must not dictate the UI, so a
@@ -538,6 +558,74 @@ async function adoptSession(s: Session): Promise<void> {
   void refreshNotifications();
 }
 
+// The cold-start "no connection — go offline?" dialog. bootstrap raises it and awaits the choice
+// here; App.svelte's dialog buttons call resolveOfflinePrompt.
+const BOOT_REACHABILITY_TIMEOUT_MS = 3000;
+let offlinePromptResolve: ((goOffline: boolean) => void) | null = null;
+
+/** resolveOfflinePrompt answers the cold-start "no connection — go offline?" dialog (App.svelte). */
+export function resolveOfflinePrompt(goOffline: boolean): void {
+  app.offlinePrompt = false;
+  const resolve = offlinePromptResolve;
+  offlinePromptResolve = null;
+  resolve?.(goOffline);
+}
+
+/** promptOfflineChoice raises the dialog and resolves to the player's choice (true = go offline). */
+function promptOfflineChoice(): Promise<boolean> {
+  app.offlinePrompt = true;
+  return new Promise<boolean>((resolve) => {
+    offlinePromptResolve = resolve;
+  });
+}
+
+/**
+ * initNetworkReactivity reacts to mid-session network changes (e.g. the player toggling flight mode):
+ * losing the network interface enters offline mode automatically (session-only); regaining it
+ * verifies the gateway is really reachable (an interface being up does not guarantee it) and returns
+ * to online — but only if the offline was auto. A deliberate offline (the Settings toggle or the
+ * cold-start dialog) is left as the player's choice. These are passive OS events — no polling, no
+ * battery cost. Web-only and skipped in the mock (the e2e drives connectivity directly).
+ */
+// While in auto-offline, poll for the network to return so the app comes back online — robust to the
+// unreliable `online` event (which often does not fire in an installed PWA). Each tick is cheap: it
+// reads navigator.onLine (no radio) and only hits the network (a reachability check) when the
+// interface is actually up, so while flight mode is on it costs nothing. The poll runs ONLY in
+// auto-offline (a deliberate offline is the player's choice) and stops on returning online.
+let recoveryTimer: ReturnType<typeof setTimeout> | null = null;
+export function scheduleRecovery(delayMs: number): void {
+  if (recoveryTimer) {
+    clearTimeout(recoveryTimer);
+    recoveryTimer = null;
+  }
+  if (typeof window === 'undefined' || !offlineMode.active || !offlineMode.auto) return;
+  recoveryTimer = setTimeout(async () => {
+    recoveryTimer = null;
+    if (!offlineMode.active || !offlineMode.auto) return;
+    const interfaceUp = typeof navigator === 'undefined' || navigator.onLine;
+    if (interfaceUp && (await checkReachable(BOOT_REACHABILITY_TIMEOUT_MS))) {
+      if (offlineMode.active && offlineMode.auto) setOfflineMode(false);
+      return;
+    }
+    scheduleRecovery(4000);
+  }, delayMs);
+}
+
+export function initNetworkReactivity(): void {
+  if (typeof window === 'undefined' || import.meta.env.MODE === 'mock') return;
+  window.addEventListener('offline', () => {
+    if (!offlineMode.active) {
+      setOfflineMode(true, false); // auto (session)
+      scheduleRecovery(4000); // poll for the network to return
+    }
+  });
+  // The online event, when it fires, just kicks an immediate reachability check; the poll above is
+  // the reliable fallback for platforms where it does not fire.
+  window.addEventListener('online', () => {
+    if (offlineMode.active && offlineMode.auto) scheduleRecovery(0);
+  });
+}
+
 /**
  * applyLinkResult applies a completed account link or merge: it adopts a
  * switched session (a guest initiator whose durable counterpart won, so the active
@@ -637,17 +725,37 @@ function syncTelegramSafeArea(): void {
   root.classList.toggle('tg-fullscreen', top > 0);
 }
 
+// The soft-keyboard height threshold (px) that distinguishes an open keyboard from browser chrome
+// (an address bar shrinks the visual viewport by far less), used to gate the focus-into-view scroll.
+const KEYBOARD_MIN_PX = 120;
+
 /**
- * syncViewportHeight mirrors the visual-viewport height into the --vvh CSS var so a screen can
+ * syncViewport mirrors the visual viewport into CSS vars so the pinned app-shell (app.css
- * fit the visible area above an open soft keyboard (iOS does not shrink dvh for the keyboard).
+ * `html.app-shell body`) both FITS (`--vvh`) and FOLLOWS (`--vv-top`) the visible area above the soft
- * On a screen whose input sits at the bottom (chat, word-check) this keeps the input visible
+ * keyboard. iOS Safari / WKWebView does not shrink the layout viewport for the keyboard (Android
- * without the page scrolling, so the layout no longer jumps when the keyboard appears.
+ * Chrome does); instead the visual viewport shrinks AND offsets down to reveal the focused field, and
+ * those values do not always cleanly revert. Tracking only the height left the top-anchored shell
+ * misaligned on iOS — empty space below the content, worst on a repeat focus; tracking offsetTop too
+ * keeps the shell on the visible area on every platform. On the keyboard-OPEN transition it also
+ * scrolls the focused field into view, since iOS does not reliably scroll a pinned document to it.
  */
-function syncViewportHeight(): void {
+let keyboardOpen = false;
+function syncViewport(): void {
   if (typeof document === 'undefined') return;
-  const vv = typeof window !== 'undefined' ? window.visualViewport : null;
+  const win = typeof window !== 'undefined' ? window : null;
-  const h = vv ? vv.height : typeof window !== 'undefined' ? window.innerHeight : 0;
+  const vv = win ? win.visualViewport : null;
+  const h = vv ? vv.height : win ? win.innerHeight : 0;
+  const top = vv ? vv.offsetTop : 0;
   if (h > 0) document.documentElement.style.setProperty('--vvh', `${h}px`);
+  document.documentElement.style.setProperty('--vv-top', `${top}px`);
+  const open = !!vv && !!win && win.innerHeight - h > KEYBOARD_MIN_PX;
+  if (open && !keyboardOpen) {
+    const el = document.activeElement;
+    if (el instanceof HTMLElement && (el.tagName === 'INPUT' || el.tagName === 'TEXTAREA')) {
+      requestAnimationFrame(() => el.scrollIntoView({ block: 'center' }));
+    }
+  }
+  keyboardOpen = open;
 }
 
 /**
@@ -707,11 +815,23 @@ export async function bootstrap(): Promise<void> {
     setLocale(guess);
   }
 
-  // Track the visual-viewport height so screens fit above an open soft keyboard (--vvh).
+  // Track the visual viewport (height + offset) so screens fit and follow the visible area above an
-  syncViewportHeight();
+  // open soft keyboard (--vvh / --vv-top). Both resize AND scroll fire on iOS when the keyboard moves
+  // the visual viewport.
+  syncViewport();
   if (typeof window !== 'undefined' && window.visualViewport) {
-    window.visualViewport.addEventListener('resize', syncViewportHeight);
+    window.visualViewport.addEventListener('resize', syncViewport);
-    window.visualViewport.addEventListener('scroll', syncViewportHeight);
+    window.visualViewport.addEventListener('scroll', syncViewport);
+  }
+
+  // Enter on a single-line <input> dismisses the soft keyboard (blur): the keyboard's default
+  // return/"Go" key otherwise does nothing on a bare input, which reads as stuck. A <textarea> (the
+  // feedback form) is excluded so Enter still inserts a newline; a form's own Enter→submit still
+  // fires first (this listener is on the document, so it runs after the field's own handler).
+  if (typeof document !== 'undefined') {
+    document.addEventListener('keydown', (e) => {
+      if (e.key === 'Enter' && e.target instanceof HTMLInputElement) e.target.blur();
+    });
   }
 
   // Load the Telegram Mini App SDK dynamically, with a timeout, on a Telegram entry — it is no
@@ -783,11 +903,65 @@ export async function bootstrap(): Promise<void> {
     return;
   }
 
+  // On the plain web (both Mini-App branches returned above) register the install-only service
+  // worker so the app is installable — Chromium needs a registered SW, notably on Android. Web-only
+  // and skipped in the mock build; see lib/pwa.svelte.
+  registerServiceWorker();
+  // React to mid-session network changes (e.g. flight mode) for the rest of the session.
+  initNetworkReactivity();
+
+  // Deliberate offline mode carried over from a prior session: with no network the session adoption
+  // + profile fetch below would hang the splash, so skip them and launch straight from the cached
+  // session + profile into the offline lobby. Without a cached profile (e.g. storage cleared) fall
+  // through to the normal online flow but KEEP the sticky flag — the mode is the player's choice, and
+  // an online boot re-persists the profile so the next launch goes offline. (A truly offline launch
+  // with no cached profile is unreachable: enabling offline requires a prior online session.)
+  if (offlineMode.active) {
+    const [offlineSession, offlineProfile] = await Promise.all([loadSession(), loadProfile()]);
+    if (shouldBootOffline({ offlineActive: true, hasSession: !!offlineSession, hasProfile: !!offlineProfile })) {
+      gateway.setToken(offlineSession!.token);
+      app.session = offlineSession!;
+      app.profile = offlineProfile!;
+      if (router.route.name === 'login' || router.route.name === 'confirm') navigate('/');
+      app.ready = true;
+      return;
+    }
+  }
+
   const saved = await loadSession();
   // A VK ID web-link callback (?code&device_id&state) rides the URL after the redirect back
   // from VK; capture and clear it here (it needs the restored session to link against).
   const vkcb = pendingVKLink();
   if (saved) {
+    // Cold-start network auto-detect (deliberate offline is handled above). With a cached profile to
+    // fall back on and no pending VK-link, do not hang on adoptSession's retrying profile fetch when
+    // the network is down: a device with no network interface goes offline for the session (no
+    // dialog); an interface that is up but cannot reach the gateway within a short window asks the
+    // player. Web-only reaches here (the Mini-App branches returned above), so isStandalone gates it.
+    const cachedProfile = await loadProfile();
+    const canOffline = !!cachedProfile && !vkcb && isStandalone() && !!cachedProfile.email;
+    if (canOffline) {
+      const interfaceOffline = typeof navigator !== 'undefined' && navigator.onLine === false;
+      gateway.setToken(saved.token);
+      const reachable = interfaceOffline ? false : await checkReachable(BOOT_REACHABILITY_TIMEOUT_MS);
+      if (!reachable) {
+        // No network interface → go offline for the session (no dialog); interface up but the
+        // gateway is unreachable → ambiguous, so ask.
+        const goOffline = interfaceOffline ? true : await promptOfflineChoice();
+        if (goOffline) {
+          // A deliberate dialog choice is sticky; an auto (no-interface) offline is session-only.
+          setOfflineMode(true, !interfaceOffline);
+          if (interfaceOffline) scheduleRecovery(4000); // auto-offline: poll for the network to return
+          app.session = saved;
+          app.profile = cachedProfile;
+          if (router.route.name === 'login' || router.route.name === 'confirm') navigate('/');
+          app.ready = true;
+          return;
+        }
+        // "Нет" — keep trying online: fall through to adoptSession (it retries; the connection
+        // watcher shows "Connecting…").
+      }
+    }
     await adoptSession(saved);
     if (vkcb) {
       // The full-page redirect lost the in-app route, so hand the callback to Profile, which
@@ -974,7 +1148,7 @@ export async function loginGuest(): Promise<void> {
 
 export async function requestEmailCode(email: string): Promise<boolean> {
   try {
-    await gateway.authEmailRequest(email, app.locale);
+    await gateway.authEmailRequest(email, app.locale, isStandalone());
     return true;
   } catch (err) {
     handleError(err);
@@ -1016,6 +1190,7 @@ export async function logout(): Promise<void> {
   app.splashDone = false;
   gateway.setToken(null);
   await clearSession();
+  await clearProfile();
   app.session = null;
   app.profile = null;
   navigate('/login');
@@ -1167,4 +1342,11 @@ if (import.meta.env.MODE === 'mock' && typeof window !== 'undefined') {
     closeStream();
     app.blocked = { blocked: true, permanent: true, until: '', reason: '', ...b };
   };
+  // Expose the router so the e2e can assert navigate() updates the route synchronously (no
+  // hashchange lag): a route that trailed the hash for a frame let bootstrap's `app.ready` flip
+  // render the previous route under the new screen (the empty-hash lobby flashing under login).
+  (window as unknown as { __router?: { navigate(p: string): void; route(): string } }).__router = {
+    navigate,
+    route: () => router.route.name,
+  };
 }

ui/src/lib/client.ts

@@ -65,7 +65,7 @@ export interface GatewayClient {
    *  cosmetic seed for a brand-new account). */
   authVK(params: string, displayName: string): Promise<Session>;
   authGuest(locale?: string): Promise<Session>;
-  authEmailRequest(email: string, language: string): Promise<void>;
+  authEmailRequest(email: string, language: string, pwa: boolean): Promise<void>;
   authEmailLogin(email: string, code: string): Promise<Session>;
   /** Confirm a one-tap email deeplink token: a login returns a session to adopt; a
    *  link returns a status ('confirmed' | 'merge_required'). */

ui/src/lib/codec.test.ts

@@ -122,10 +122,11 @@ describe('codec', () => {
     expect(guest.browserTz()).toBe('-05:30');
 
     const email = fb.EmailRequestRequest.getRootAsEmailRequestRequest(
-      new ByteBuffer(encodeEmailRequest('a@example.com', '+00:00', 'en')),
+      new ByteBuffer(encodeEmailRequest('a@example.com', '+00:00', 'en', true)),
     );
     expect(email.email()).toBe('a@example.com');
     expect(email.browserTz()).toBe('+00:00');
+    expect(email.pwa()).toBe(true);
     expect(email.language()).toBe('en');
 
     const confirm = fb.EmailConfirmLinkRequest.getRootAsEmailConfirmLinkRequest(
@@ -711,6 +712,28 @@ describe('codec', () => {
     expect(decodeProfile(b.asUint8Array()).variantPreferences).toEqual(['erudit_ru', 'scrabble_en']);
   });
 
+  it('decodes the profile dictionary versions into a per-variant map', () => {
+    const b = new Builder(128);
+    const uid = b.createString('u-1');
+    const en = fb.DictVersion.createDictVersion(b, b.createString('scrabble_en'), b.createString('v1.3.0'));
+    const er = fb.DictVersion.createDictVersion(b, b.createString('erudit_ru'), b.createString('v1.2.0'));
+    const vec = fb.Profile.createDictVersionsVector(b, [en, er]);
+    fb.Profile.startProfile(b);
+    fb.Profile.addUserId(b, uid);
+    fb.Profile.addDictVersions(b, vec);
+    b.finish(fb.Profile.endProfile(b));
+    expect(decodeProfile(b.asUint8Array()).dictVersions).toEqual({ scrabble_en: 'v1.3.0', erudit_ru: 'v1.2.0' });
+  });
+
+  it('decodes an absent dict_versions vector to an empty map', () => {
+    const b = new Builder(64);
+    const uid = b.createString('u-1');
+    fb.Profile.startProfile(b);
+    fb.Profile.addUserId(b, uid);
+    b.finish(fb.Profile.endProfile(b));
+    expect(decodeProfile(b.asUint8Array()).dictVersions).toEqual({});
+  });
+
   it('encodes the update-profile variant preferences', () => {
     const buf = encodeUpdateProfile({
       displayName: 'Kaya',

ui/src/lib/codec.ts

@@ -214,7 +214,12 @@ export function encodeGuestLogin(locale: string, browserTz: string): Uint8Array
   return finish(b, fb.GuestLoginRequest.endGuestLoginRequest(b));
 }
 
-export function encodeEmailRequest(email: string, browserTz: string, language: string): Uint8Array {
+export function encodeEmailRequest(
+  email: string,
+  browserTz: string,
+  language: string,
+  pwa: boolean,
+): Uint8Array {
   const b = new Builder(128);
   const e = b.createString(email);
   const tz = b.createString(browserTz);
@@ -223,6 +228,7 @@ export function encodeEmailRequest(email: string, browserTz: string, language: s
   fb.EmailRequestRequest.addEmail(b, e);
   fb.EmailRequestRequest.addBrowserTz(b, tz);
   fb.EmailRequestRequest.addLanguage(b, l);
+  fb.EmailRequestRequest.addPwa(b, pwa);
   return finish(b, fb.EmailRequestRequest.endEmailRequestRequest(b));
 }
 
@@ -358,9 +364,25 @@ export function decodeProfile(buf: Uint8Array): Profile {
     email: s(p.email()),
     telegramLinked: p.telegramLinked(),
     vkLinked: p.vkLinked(),
+    dictVersions: decodeDictVersions(p),
   };
 }
 
+// decodeDictVersions reads the profile's per-variant current dictionary versions into a
+// variant-keyed map, so the offline preloader can look up the version for each enabled
+// variant. An entry with an unknown variant or empty version is skipped.
+function decodeDictVersions(p: fb.Profile): Partial<Record<Variant, string>> {
+  const out: Partial<Record<Variant, string>> = {};
+  for (let i = 0; i < p.dictVersionsLength(); i++) {
+    const dv = p.dictVersions(i);
+    if (!dv) continue;
+    const variant = s(dv.variant()) as Variant;
+    const version = s(dv.version());
+    if (variant && version) out[variant] = version;
+  }
+  return out;
+}
+
 // decodeVariantPreferences reads the Profile.variant_preferences vector (the variants
 // the player enabled in Settings).
 function decodeVariantPreferences(p: fb.Profile): Variant[] {
@@ -439,6 +461,7 @@ function decodeStateViewTable(v: fb.StateView): StateView {
     bagLen: v.bagLen(),
     hintsRemaining: v.hintsRemaining(),
     walletBalance: v.walletBalance(),
+    hintUnlockLeftSeconds: v.hintUnlockLeftSeconds(),
   };
 }
 

ui/src/lib/connection.svelte.ts

@@ -9,6 +9,7 @@
 // other traffic is in flight.
 
 import { backoffMs } from './retry';
+import { offlineMode } from './offline.svelte';
 
 let online = $state(true);
 let watchTimer: ReturnType<typeof setTimeout> | null = null;
@@ -27,6 +28,24 @@ export function registerProbe(fn: () => Promise<void>): void {
   probe = fn;
 }
 
+/**
+ * checkReachable runs the reachability probe once, bounded by timeoutMs, and reports whether the
+ * gateway answered — a single attempt (no retry loop), for the cold-start network decision — while
+ * updating the online signal. It reports false when no probe is registered or the timeout wins.
+ */
+export async function checkReachable(timeoutMs: number): Promise<boolean> {
+  if (!probe) return false;
+  try {
+    await Promise.race([
+      probe(),
+      new Promise<never>((_, reject) => setTimeout(() => reject(new Error('reachability timeout')), timeoutMs)),
+    ]);
+    return true;
+  } catch {
+    return false;
+  }
+}
+
 /** reportOnline marks the gateway reachable and stops the watcher. */
 export function reportOnline(): void {
   online = true;
@@ -51,7 +70,9 @@ function scheduleProbe(attempt: number): void {
   watchTimer = setTimeout(
     () => {
       watchTimer = null;
-      if (online || !probe) return;
+      // Never probe the network in offline mode (the kill switch); the online/offline events drive
+      // recovery there instead.
+      if (online || !probe || offlineMode.active) return;
       probe().then(reportOnline, () => scheduleProbe(Math.min(attempt + 1, 6)));
     },
     backoffMs(attempt),

ui/src/lib/dict/dawg.cursor.test.ts

@@ -0,0 +1,68 @@
+import { describe, it, expect } from 'vitest';
+import { readFileSync } from 'node:fs';
+import { Dawg } from './dawg';
+
+// The step-by-step DAWG cursor (root/final/next/arcs) is the primitive the move
+// generator walks. These fast unit tests pin it against a small committed sample
+// dictionary (backend/cmd/movegen); the full parity vs the Go solver lands with
+// the generator's conformance fixtures.
+const bytes = new Uint8Array(readFileSync(new URL('./testdata/sample_en.dawg', import.meta.url)));
+const fixture = JSON.parse(
+  readFileSync(new URL('./testdata/sample_en.words.json', import.meta.url), 'utf8'),
+) as { numAdded: number; words: string[]; indexes: number[][] };
+
+const key = (w: number[]): string => w.join(',');
+
+// enumerateWords walks the whole automaton depth-first, collecting the index path
+// at every accepting node — i.e. every stored word.
+function enumerateWords(d: Dawg): number[][] {
+  const out: number[][] = [];
+  const path: number[] = [];
+  const visit = (node: number): void => {
+    d.arcs(node, (label, dest, final) => {
+      path.push(label);
+      if (final) out.push(path.slice());
+      visit(dest);
+      path.pop();
+      return true;
+    });
+  };
+  if (d.final(d.root())) out.push([]);
+  visit(d.root());
+  return out;
+}
+
+describe('dawg cursor', () => {
+  it('parses the sample fixture', () => {
+    const d = new Dawg(bytes);
+    expect(d.numAdded).toBe(fixture.numAdded);
+  });
+
+  it('root is not an accepting state (the sample has no empty word)', () => {
+    const d = new Dawg(bytes);
+    expect(d.final(d.root())).toBe(false);
+  });
+
+  it('enumerates exactly the stored words', () => {
+    const d = new Dawg(bytes);
+    const got = enumerateWords(d).map(key).sort();
+    const want = fixture.indexes.map(key).sort();
+    expect(got).toEqual(want);
+  });
+
+  it('next walks a stored word to an accepting node and rejects a non-edge', () => {
+    const d = new Dawg(bytes);
+    let node = d.root();
+    for (const ch of [2, 0, 17, 4, 3]) {
+      // "cared"
+      node = d.next(node, ch);
+      expect(node).toBeGreaterThanOrEqual(0);
+    }
+    expect(d.final(node)).toBe(true);
+    // "care" (index [2,0,17,4]) is an internal accepting node on the way to "cared".
+    const care = [2, 0, 17, 4].reduce((n, ch) => d.next(n, ch), d.root());
+    expect(d.final(care)).toBe(true);
+    // No stored word starts with 'z' (index 25).
+    expect(d.next(d.root(), 25)).toBe(-1);
+  });
+});

ui/src/lib/dict/dawg.ts

@@ -95,6 +95,85 @@ export class Dawg {
     return this.indexOf(word) >= 0;
   }
 
+  // --- Step-by-step traversal (the move generator's primitive) ---------------
+  //
+  // A `Node` is a bit offset into the graph; 0 denotes the root (which resolves
+  // to firstNodeOffset). These mirror dafsa's traverse.go Cursor (Root/Final/
+  // Next/Arcs) over the same bitstream this reader already decodes, so the ported
+  // generator can drive the automaton one transition at a time. Single-threaded
+  // JS shares this reader's position across calls; every method re-seeks to its
+  // node on entry, and arcs brackets the callback with a save/restore, so nested
+  // use during a walk is safe. Mirrors dafsa (*Cursor).
+
+  /** root returns the start state of the automaton. */
+  root(): number {
+    return 0;
+  }
+
+  /** final reports whether node is an accepting state (a stored word ends there). */
+  final(node: number): boolean {
+    if (this.numEdges <= 0) {
+      return this.hasEmptyWord && node === 0;
+    }
+    this.p = node === 0 ? this.firstNodeOffset : node;
+    return this.readBits(1) === 1;
+  }
+
+  /**
+   * next follows the edge labelled ch (an alphabet index) from node, returning the
+   * destination node, or -1 when no such edge exists.
+   */
+  next(node: number, ch: number): number {
+    return this.getEdge(node, ch) ? this.eNode : -1;
+  }
+
+  /**
+   * arcs calls fn for each out-edge of node in ascending label order, passing the
+   * edge's label, its destination node and whether that destination is accepting.
+   * It stops early if fn returns false. Mirrors dafsa (*Cursor).Arcs.
+   */
+  arcs(node: number, fn: (label: number, dest: number, final: boolean) => boolean): void {
+    if (this.numEdges <= 0) {
+      return;
+    }
+    this.p = node === 0 ? this.firstNodeOffset : node;
+    this.readBits(1); // node final flag — not needed here
+    const fallthrough = this.readBits(1);
+
+    if (fallthrough === 1) {
+      const label = this.readBits(this.cbits);
+      // The reader now sits at the destination node, whose first bit is its final flag.
+      const dest = this.p;
+      const final = this.readBits(1) === 1;
+      fn(label, dest, final);
+      return;
+    }
+
+    const nskiplen = bitsLen(this.wbits);
+    let nskip = 0;
+    let numEdges = 1;
+    if (this.readBits(1) !== 1) {
+      // not a single edge
+      numEdges = this.readUnsigned();
+      nskip = this.readBits(nskiplen);
+    }
+
+    for (let i = 0; i < numEdges; i++) {
+      const label = this.readBits(this.cbits);
+      if (i > 0) {
+        this.readBits(nskip); // per-edge skip count, unused for traversal
+      }
+      const dest = this.readBits(this.abits);
+      const resume = this.p;
+      this.p = dest;
+      const final = this.readBits(1) === 1;
+      if (!fn(label, dest, final)) {
+        return;
+      }
+      this.p = resume;
+    }
+  }
+
   // getEdge resolves the outgoing edge for ch from the node at the given bit
   // offset. On success it fills eNode/eCount/eFinal and returns true. Mirrors
   // dafsa (*dawg).getEdge.

ui/src/lib/dict/generate.parity.test.ts

@@ -0,0 +1,99 @@
+import { describe, it, expect } from 'vitest';
+import { readFileSync } from 'node:fs';
+import { Dawg } from './dawg';
+import { generateMoves, GenRack, type GenBoard, type Mode } from './generate';
+import type { Ruleset } from './validate';
+
+// Conformance gate for the ported move generator: for each committed position it must
+// return exactly the ranked play list the real Go solver returns (backend/cmd/movegen).
+// The Russian sample reaches alphabet index 32, exercising the 33-letter cross-set.
+
+interface Tile {
+  row: number;
+  col: number;
+  letter: number;
+  blank: boolean;
+}
+interface GenMove {
+  dir: number;
+  tiles: Tile[];
+  score: number;
+}
+interface Fixture {
+  ruleset: {
+    size: number;
+    cols: number;
+    center: number;
+    rackSize: number;
+    bingo: number;
+    values: number[];
+    letterMult: number[][];
+    wordMult: number[][];
+  };
+  cases: {
+    name: string;
+    placed: Tile[] | null;
+    rack: { letters: number[]; blanks: number };
+    mode: number;
+    ignoreCrossWords: boolean;
+    moves: GenMove[];
+  }[];
+}
+
+function load(tag: string): { dawg: Dawg; fx: Fixture } {
+  const bytes = new Uint8Array(readFileSync(new URL(`./testdata/sample_${tag}.dawg`, import.meta.url)));
+  const fx = JSON.parse(
+    readFileSync(new URL(`./testdata/sample_${tag}.gen.json`, import.meta.url), 'utf8'),
+  ) as Fixture;
+  return { dawg: new Dawg(bytes), fx };
+}
+
+function buildBoard(placed: Tile[], cols: number): GenBoard {
+  const grid: ({ letter: number; blank: boolean } | null)[] = new Array(cols * cols).fill(null);
+  for (const t of placed) grid[t.row * cols + t.col] = { letter: t.letter, blank: t.blank };
+  const inBounds = (r: number, c: number): boolean => r >= 0 && r < cols && c >= 0 && c < cols;
+  return {
+    rows: cols,
+    cols,
+    inBounds,
+    filled: (r, c) => inBounds(r, c) && grid[r * cols + c] !== null,
+    cellAt: (r, c) => grid[r * cols + c]!,
+    isEmpty: () => placed.length === 0,
+  };
+}
+
+function rulesetFor(fx: Fixture, ignoreCrossWords: boolean): Ruleset {
+  const r = fx.ruleset;
+  return {
+    cols: r.cols,
+    center: r.center,
+    rackSize: r.rackSize,
+    bingo: r.bingo,
+    values: r.values,
+    letterMult: (row, col) => r.letterMult[row][col],
+    wordMult: (row, col) => r.wordMult[row][col],
+    ignoreCrossWords,
+  };
+}
+
+// sig is an order-stable signature of a move: orientation, score and its placed tiles
+// sorted by square — so two lists compare equal iff they rank the same plays the same way.
+function sig(m: GenMove): string {
+  const ts = m.tiles.slice().sort((a, b) => (a.row !== b.row ? a.row - b.row : a.col - b.col));
+  return `${m.dir}#${m.score}#` + ts.map((t) => `${t.row},${t.col},${t.letter}${t.blank ? '*' : ''}`).join(';');
+}
+
+for (const tag of ['en', 'ru']) {
+  describe(`move generator parity vs Go solver (${tag})`, () => {
+    const { dawg, fx } = load(tag);
+    for (const c of fx.cases) {
+      it(c.name, () => {
+        const board = buildBoard(c.placed ?? [], fx.ruleset.cols);
+        const rack = GenRack.from(fx.ruleset.size, c.rack.letters, c.rack.blanks);
+        const rs = rulesetFor(fx, c.ignoreCrossWords);
+        const got = generateMoves(dawg, board, rack, rs, c.mode as Mode);
+        expect(got.map(sig)).toEqual(c.moves.map(sig));
+      });
+    }
+  });
+}

ui/src/lib/dict/generate.realparity.test.ts

@@ -0,0 +1,113 @@
+import { describe, it, expect } from 'vitest';
+import { readFileSync, existsSync } from 'node:fs';
+import { join } from 'node:path';
+import { Dawg } from './dawg';
+import { generateMoves, GenRack, type GenBoard, type Mode } from './generate';
+import type { Ruleset } from './validate';
+
+// Full-dictionary conformance for the ported move generator: for positions over the real
+// shipped dictionaries (deep graphs and full 26/33-letter alphabets the tiny committed
+// samples cannot reach) it must return exactly the ranked list the Go solver does. The
+// golden vectors come from `go run ./backend/cmd/movegen -dawg-dir <dawg> -out <dir>` and
+// the CI conformance job wires the two directories in; the suite skips when they are unset.
+const dawgDir = process.env.DICT_DAWG_DIR;
+const goldDir = process.env.DICT_MOVEGEN_DIR;
+const ready = !!dawgDir && !!goldDir && existsSync(dawgDir) && existsSync(goldDir);
+
+// variant -> the release dawg file name (matches dawg.parity.test.ts / the movegen tool).
+const variants = [
+  { variant: 'scrabble_en', dawg: 'en_sowpods' },
+  { variant: 'scrabble_ru', dawg: 'ru_scrabble' },
+  { variant: 'erudit_ru', dawg: 'ru_erudit' },
+];
+
+interface Tile {
+  row: number;
+  col: number;
+  letter: number;
+  blank: boolean;
+}
+interface GenMove {
+  dir: number;
+  tiles: Tile[];
+  score: number;
+}
+interface Fixture {
+  ruleset: {
+    size: number;
+    cols: number;
+    center: number;
+    rackSize: number;
+    bingo: number;
+    values: number[];
+    letterMult: number[][];
+    wordMult: number[][];
+  };
+  cases: {
+    name: string;
+    placed: Tile[] | null;
+    rack: { letters: number[]; blanks: number };
+    mode: number;
+    ignoreCrossWords: boolean;
+    moves: GenMove[];
+  }[];
+}
+
+function buildBoard(placed: Tile[], cols: number): GenBoard {
+  const grid: ({ letter: number; blank: boolean } | null)[] = new Array(cols * cols).fill(null);
+  for (const t of placed) grid[t.row * cols + t.col] = { letter: t.letter, blank: t.blank };
+  const inBounds = (r: number, c: number): boolean => r >= 0 && r < cols && c >= 0 && c < cols;
+  return {
+    rows: cols,
+    cols,
+    inBounds,
+    filled: (r, c) => inBounds(r, c) && grid[r * cols + c] !== null,
+    cellAt: (r, c) => grid[r * cols + c]!,
+    isEmpty: () => placed.length === 0,
+  };
+}
+
+function rulesetFor(fx: Fixture, ignoreCrossWords: boolean): Ruleset {
+  const r = fx.ruleset;
+  return {
+    cols: r.cols,
+    center: r.center,
+    rackSize: r.rackSize,
+    bingo: r.bingo,
+    values: r.values,
+    letterMult: (row, col) => r.letterMult[row][col],
+    wordMult: (row, col) => r.wordMult[row][col],
+    ignoreCrossWords,
+  };
+}
+
+function sig(m: GenMove): string {
+  const ts = m.tiles.slice().sort((a, b) => (a.row !== b.row ? a.row - b.row : a.col - b.col));
+  return `${m.dir}#${m.score}#` + ts.map((t) => `${t.row},${t.col},${t.letter}${t.blank ? '*' : ''}`).join(';');
+}
+
+describe.skipIf(!ready)('move generator parity vs Go on the real dictionaries', () => {
+  for (const v of variants) {
+    describe(v.variant, () => {
+      // Guard the collection-time reads: the block is skipped when the dirs are unset, but
+      // the describe callback still runs to register tests, so touch the filesystem only
+      // when ready (otherwise join(undefined, …) would throw during a normal unit run).
+      if (!ready) return;
+      const fx = JSON.parse(readFileSync(join(goldDir!, `${v.variant}.movegen.json`), 'utf8')) as Fixture;
+      const dawg = new Dawg(new Uint8Array(readFileSync(join(dawgDir!, `${v.dawg}.dawg`))));
+      for (const c of fx.cases) {
+        it(
+          c.name,
+          () => {
+            const board = buildBoard(c.placed ?? [], fx.ruleset.cols);
+            const rack = GenRack.from(fx.ruleset.size, c.rack.letters, c.rack.blanks);
+            const rs = rulesetFor(fx, c.ignoreCrossWords);
+            const got = generateMoves(dawg, board, rack, rs, c.mode as Mode);
+            expect(got.map(sig)).toEqual(c.moves.map(sig));
+          },
+          60_000,
+        );
+      }
+    });
+  }
+});

ui/src/lib/dict/generate.ts

@@ -0,0 +1,418 @@
+// Local move generator: every legal play for a rack on a board, ranked by
+// descending score. Ported from the scrabble-solver engine — the Appel-Jacobson
+// two-phase algorithm (LeftPart then ExtendRight) over a plain left-to-right DAWG
+// (scrabble/gen_dawg.go, gen.go, crossset.go, solver.go, key.go). It walks the DAWG
+// with the cursor from dawg.ts and scores each play with evaluate() from validate.ts,
+// so the whole robot brain runs on-device. Faithfulness to the Go solver is pinned by
+// generate.parity.test.ts against golden fixtures (backend/cmd/movegen).
+//
+// Everything works in alphabet-index space, mirroring the Go engine. A letterSet is
+// a per-square cross-set (the letters that form a legal perpendicular word there);
+// it is a boolean membership array rather than a uint64, so alphabet indexes past
+// JS's 31-bit shift boundary (Russian has 33 letters) are handled exactly.
+
+import { Dawg } from './dawg';
+import {
+  evaluate,
+  connected,
+  Horizontal,
+  Vertical,
+  type Board,
+  type Ruleset,
+  type Move,
+  type Placement,
+  type Direction,
+} from './validate';
+
+/** Both generates across plays (on the board) and down plays (on its transpose). */
+export const Both = 0;
+/** OnlyHorizontal generates across plays only. */
+export const OnlyHorizontal = 1;
+/** OnlyVertical generates down plays only (Эрудит plays a single orientation per turn). */
+export const OnlyVertical = 2;
+export type Mode = typeof Both | typeof OnlyHorizontal | typeof OnlyVertical;
+
+function modeIncludes(mode: Mode, dir: Direction): boolean {
+  if (mode === Both) return true;
+  if (mode === OnlyHorizontal) return dir === Horizontal;
+  return dir === Vertical;
+}
+
+/**
+ * GenBoard is the board view the generator needs: the validator's read view plus the
+ * dimensions it iterates over. The whole board is square, so a transposed view (below)
+ * satisfies the same shape.
+ */
+export interface GenBoard extends Board {
+  rows: number;
+  cols: number;
+}
+
+/**
+ * GenRack is a rack as per-letter tile counts plus a blank slot, mirroring
+ * scrabble-solver/rack. The generator mutates a single rack in place — removing a
+ * tile, recursing, putting it back — so the operations are O(1) and allocation-free.
+ */
+export class GenRack {
+  private readonly counts: Int32Array;
+
+  /** Construct an empty rack for an alphabet of the given size (a trailing blank slot). */
+  constructor(size: number) {
+    this.counts = new Int32Array(size + 1);
+  }
+
+  /** from builds a rack from a multiset of letter indexes plus a blank count. */
+  static from(size: number, letters: readonly number[], blanks: number): GenRack {
+    const r = new GenRack(size);
+    for (const l of letters) r.counts[l]++;
+    r.counts[size] += blanks;
+    return r;
+  }
+
+  /** has reports whether at least one tile of the letter index is on the rack. */
+  has(letter: number): boolean {
+    return this.counts[letter] > 0;
+  }
+  /** blanks returns how many blank tiles are on the rack. */
+  blanks(): number {
+    return this.counts[this.counts.length - 1];
+  }
+  remove(letter: number): void {
+    this.counts[letter]--;
+  }
+  add(letter: number): void {
+    this.counts[letter]++;
+  }
+  removeBlank(): void {
+    this.counts[this.counts.length - 1]--;
+  }
+  addBlank(): void {
+    this.counts[this.counts.length - 1]++;
+  }
+  /** clone returns an independent copy. */
+  clone(): GenRack {
+    const c = new GenRack(this.counts.length - 1);
+    c.counts.set(this.counts);
+    return c;
+  }
+}
+
+// --- cross-sets ------------------------------------------------------------------
+//
+// A LetterSet is membership over alphabet letter indexes. Mirrors scrabble.letterSet
+// (a uint64) but as a Uint8Array so index 32 (Russian) is exact under JS bit ops.
+type LetterSet = Uint8Array;
+
+function fullSet(size: number): LetterSet {
+  return new Uint8Array(size).fill(1);
+}
+
+// walk follows word (alphabet indexes) left to right from the root; -1 if it derails.
+function walk(dawg: Dawg, word: readonly number[]): number {
+  let n = dawg.root();
+  for (const l of word) {
+    n = dawg.next(n, l);
+    if (n < 0) return -1;
+  }
+  return n;
+}
+
+// completers returns the letters X (< size) whose arc from state leads directly to an
+// accepting node — the deterministic cross-set primitive. Mirrors scrabble.completers.
+function completers(dawg: Dawg, state: number, size: number): LetterSet {
+  const set = new Uint8Array(size);
+  dawg.arcs(state, (label, _dest, final) => {
+    if (final && label < size) set[label] = 1;
+    return true;
+  });
+  return set;
+}
+
+// dawgCrossSet returns the letters X for which above·X·below is a stored word. Mirrors
+// scrabble.dawgCrossSet: a right extension (no tiles below) just completes the prefix
+// above; a left extension (tiles below) probes each X. above/below are letter indexes.
+function dawgCrossSet(dawg: Dawg, above: number[], below: number[], size: number): LetterSet {
+  if (above.length === 0 && below.length === 0) return fullSet(size);
+  if (below.length === 0) {
+    const node = walk(dawg, above);
+    if (node < 0) return new Uint8Array(size);
+    return completers(dawg, node, size);
+  }
+  let node = dawg.root();
+  if (above.length > 0) {
+    node = walk(dawg, above);
+    if (node < 0) return new Uint8Array(size);
+  }
+  const set = new Uint8Array(size);
+  for (let x = 0; x < size; x++) {
+    let m = dawg.next(node, x);
+    if (m < 0) continue;
+    let ok = true;
+    for (const l of below) {
+      m = dawg.next(m, l);
+      if (m < 0) {
+        ok = false;
+        break;
+      }
+    }
+    if (ok && dawg.final(m)) set[x] = 1;
+  }
+  return set;
+}
+
+// columnContext returns the contiguous run of filled cells immediately above and below
+// the empty square (r, c), each top to bottom, as letter indexes — the tiles a
+// perpendicular word through (r, c) would include. Mirrors scrabble.columnContext.
+function columnContext(b: GenBoard, r: number, c: number): { above: number[]; below: number[] } {
+  const above: number[] = [];
+  let start = r;
+  while (start - 1 >= 0 && b.filled(start - 1, c)) start--;
+  for (let rr = start; rr < r; rr++) above.push(b.cellAt(rr, c).letter);
+
+  const below: number[] = [];
+  let end = r;
+  while (end + 1 < b.rows && b.filled(end + 1, c)) end++;
+  for (let rr = r + 1; rr <= end; rr++) below.push(b.cellAt(rr, c).letter);
+  return { above, below };
+}
+
+// transpose returns a view of b with rows and columns swapped, so down-play generation
+// runs as across generation. Mirrors board.Transpose (as a lazy view).
+function transpose(b: GenBoard): GenBoard {
+  return {
+    rows: b.cols,
+    cols: b.rows,
+    inBounds: (r, c) => b.inBounds(c, r),
+    filled: (r, c) => b.filled(c, r),
+    cellAt: (r, c) => b.cellAt(c, r),
+    isEmpty: () => b.isEmpty(),
+  };
+}
+
+// A tentatively placed left-part tile; its column is fixed only at record time.
+interface TileInfo {
+  letter: number;
+  blank: boolean;
+}
+
+// AcrossGen carries one across-generation pass over a board. Mirrors scrabble.acrossGen.
+class AcrossGen {
+  private row = 0;
+  private readonly left: TileInfo[] = [];
+  private readonly right: Placement[] = [];
+
+  constructor(
+    private readonly dawg: Dawg,
+    private readonly bd: GenBoard,
+    private readonly rk: GenRack,
+    private readonly cross: (r: number, c: number) => LetterSet,
+    private readonly emit: (placements: Placement[]) => void,
+  ) {}
+
+  generateRow(row: number, firstMove: boolean, centerRow: number, centerCol: number): void {
+    this.row = row;
+    let limit = 0;
+    for (let col = 0; col < this.bd.cols; col++) {
+      if (this.bd.filled(row, col)) {
+        limit = 0;
+        continue;
+      }
+      const anchor = firstMove ? row === centerRow && col === centerCol : this.hasFilledNeighbor(row, col);
+      if (!anchor) {
+        limit++;
+        continue;
+      }
+      this.left.length = 0;
+      this.right.length = 0;
+      if (col > 0 && this.bd.filled(row, col - 1)) {
+        const pre = this.walkPrefix(row, col);
+        if (pre.ok) this.extendRight(pre.node, col, col);
+      } else {
+        this.leftPart(this.dawg.root(), col, limit);
+      }
+      limit = 0;
+    }
+  }
+
+  private hasFilledNeighbor(r: number, c: number): boolean {
+    return this.bd.filled(r - 1, c) || this.bd.filled(r + 1, c) || this.bd.filled(r, c - 1) || this.bd.filled(r, c + 1);
+  }
+
+  // walkPrefix walks the DAWG through the filled run ending at col-1, returning the
+  // node reached and whether that prefix exists. Mirrors scrabble.acrossGen.walkPrefix.
+  private walkPrefix(row: number, col: number): { node: number; ok: boolean } {
+    let start = col - 1;
+    while (start - 1 >= 0 && this.bd.filled(row, start - 1)) start--;
+    let node = this.dawg.root();
+    for (let c = start; c < col; c++) {
+      node = this.dawg.next(node, this.bd.cellAt(row, c).letter);
+      if (node < 0) return { node, ok: false };
+    }
+    return { node, ok: true };
+  }
+
+  // leftPart places left-part tiles from the rack (up to limit), calling extendRight
+  // after each prefix. Mirrors scrabble.acrossGen.leftPart.
+  private leftPart(node: number, anchorCol: number, limit: number): void {
+    this.extendRight(node, anchorCol, anchorCol);
+    if (limit === 0) return;
+    this.dawg.arcs(node, (label, dest) => {
+      if (this.rk.has(label)) {
+        this.rk.remove(label);
+        this.left.push({ letter: label, blank: false });
+        this.leftPart(dest, anchorCol, limit - 1);
+        this.left.pop();
+        this.rk.add(label);
+      }
+      if (this.rk.blanks() > 0) {
+        this.rk.removeBlank();
+        this.left.push({ letter: label, blank: true });
+        this.leftPart(dest, anchorCol, limit - 1);
+        this.left.pop();
+        this.rk.addBlank();
+      }
+      return true;
+    });
+  }
+
+  // extendRight extends the word rightward from col, placing rack tiles on empty
+  // squares (constrained by cross-sets) and following board tiles. A word is recorded
+  // only past the anchor. Mirrors scrabble.acrossGen.extendRight.
+  private extendRight(node: number, col: number, anchorCol: number): void {
+    if (col >= this.bd.cols) {
+      if (col > anchorCol && this.dawg.final(node)) this.record(anchorCol);
+      return;
+    }
+    if (this.bd.filled(this.row, col)) {
+      const dest = this.dawg.next(node, this.bd.cellAt(this.row, col).letter);
+      if (dest >= 0) this.extendRight(dest, col + 1, anchorCol);
+      return;
+    }
+
+    if (col > anchorCol && this.dawg.final(node)) this.record(anchorCol);
+    const cross = this.cross(this.row, col);
+    this.dawg.arcs(node, (label, dest) => {
+      if (cross[label] !== 1) return true;
+      if (this.rk.has(label)) {
+        this.rk.remove(label);
+        this.right.push({ row: this.row, col, letter: label, blank: false });
+        this.extendRight(dest, col + 1, anchorCol);
+        this.right.pop();
+        this.rk.add(label);
+      }
+      if (this.rk.blanks() > 0) {
+        this.rk.removeBlank();
+        this.right.push({ row: this.row, col, letter: label, blank: true });
+        this.extendRight(dest, col + 1, anchorCol);
+        this.right.pop();
+        this.rk.addBlank();
+      }
+      return true;
+    });
+  }
+
+  // record assembles the play (left part at fixed columns, then the right part) and
+  // reports it, skipping plays that lay no new tile. Mirrors scrabble.acrossGen.record.
+  private record(anchorCol: number): void {
+    if (this.left.length + this.right.length === 0) return;
+    const placements: Placement[] = [];
+    const leftStart = anchorCol - this.left.length;
+    for (let i = 0; i < this.left.length; i++) {
+      placements.push({ row: this.row, col: leftStart + i, letter: this.left[i].letter, blank: this.left[i].blank });
+    }
+    for (const p of this.right) placements.push(p);
+    this.emit(placements);
+  }
+}
+
+// runAcross generates all across plays on bd and reports each via emit in bd's
+// coordinates. Cross-sets are computed lazily (vertical words on bd) and cached.
+// Mirrors DAWGGenerator.runAcross.
+function runAcross(
+  dawg: Dawg,
+  bd: GenBoard,
+  rk: GenRack,
+  size: number,
+  rs: Ruleset,
+  centerRow: number,
+  centerCol: number,
+  emit: (placements: Placement[]) => void,
+): void {
+  let crossFn: (r: number, c: number) => LetterSet;
+  if (rs.ignoreCrossWords) {
+    const full = fullSet(size);
+    crossFn = () => full;
+  } else {
+    const cache = new Array<LetterSet | undefined>(bd.rows * bd.cols);
+    crossFn = (r, c) => {
+      const i = r * bd.cols + c;
+      let s = cache[i];
+      if (!s) {
+        const { above, below } = columnContext(bd, r, c);
+        s = dawgCrossSet(dawg, above, below, size);
+        cache[i] = s;
+      }
+      return s;
+    };
+  }
+
+  const ag = new AcrossGen(dawg, bd, rk, crossFn, emit);
+  const firstMove = bd.isEmpty();
+  for (let row = 0; row < bd.rows; row++) {
+    ag.generateRow(row, firstMove, centerRow, centerCol);
+  }
+}
+
+// moveKey is a canonical string identifying a play (direction plus its placed tiles),
+// used to de-duplicate and rank generated moves. Mirrors scrabble.moveKey.
+export function moveKey(dir: Direction, placements: readonly Placement[]): string {
+  const ps = placements.slice().sort((a, b) => (a.row !== b.row ? a.row - b.row : a.col - b.col));
+  let s = String(dir);
+  for (const p of ps) s += `;${p.row},${p.col},${p.letter}${p.blank ? '*' : ''}`;
+  return s;
+}
+
+/**
+ * generateMoves returns every legal play for rack on board in the mode's orientations,
+ * ranked by descending score (ties broken by the canonical move key). It walks the DAWG
+ * with the cursor and scores each play with evaluate(); the alphabet size is taken from
+ * the ruleset's value table. Mirrors (*Solver).GenerateMovesOpts (the ruleset carries
+ * ignoreCrossWords for the single-word rule).
+ */
+export function generateMoves(dawg: Dawg, board: GenBoard, rack: GenRack, rs: Ruleset, mode: Mode = Both): Move[] {
+  const size = rs.values.length;
+  const rk = rack.clone(); // generation mutates the rack in place and restores it
+  const centerRow = Math.floor(rs.center / rs.cols);
+  const centerCol = rs.center % rs.cols;
+
+  const moves: Move[] = [];
+  const seen = new Set<string>();
+  const emit = (dir: Direction, placements: Placement[]): void => {
+    const key = moveKey(dir, placements);
+    if (seen.has(key)) return;
+    const res = evaluate(board, rs, dir, placements);
+    if (res.err || !res.move) return;
+    seen.add(key);
+    moves.push(res.move);
+  };
+
+  if (modeIncludes(mode, Horizontal)) {
+    runAcross(dawg, board, rk, size, rs, centerRow, centerCol, (p) => emit(Horizontal, p));
+  }
+  if (modeIncludes(mode, Vertical)) {
+    const tb = transpose(board);
+    runAcross(dawg, tb, rk, size, rs, centerCol, centerRow, (p) => {
+      const rp = p.map((pl) => ({ row: pl.col, col: pl.row, letter: pl.letter, blank: pl.blank }));
+      emit(Vertical, rp);
+    });
+  }
+
+  const kept = moves.filter((m) => connected(board, rs, m));
+  kept.sort((a, b) => {
+    if (a.score !== b.score) return b.score - a.score;
+    const ka = moveKey(a.dir, a.tiles);
+    const kb = moveKey(b.dir, b.tiles);
+    return ka < kb ? -1 : ka > kb ? 1 : 0;
+  });
+  return kept;
+}

ui/src/lib/dict/offlineready.ts

@@ -0,0 +1,27 @@
+// Browser orchestration for the offline-toggle readiness wait. Lazily imported by
+// offline.svelte.ts's requestOffline so the dict loader/generator it pulls in stays out of the main
+// bundle. It runs the same cache-first preload as the background warmup (preload.ts), but bounded by
+// a UI wait: it tells the toggle whether flipping to offline can succeed right now, and leaves the
+// fetch running on a timeout so a later flip is instant.
+
+import type { Profile } from '../model';
+import { preloadDicts } from './preload';
+import { getDawg, dictLoadingDisabled } from '../dict';
+import { raceOfflineReady } from '../offline';
+
+/**
+ * ensureOfflineDicts fetches the profile's enabled variants' dictionaries cache-first (instant when
+ * already warm, a network fetch otherwise) and reports, within budgetMs, whether every one is
+ * available — the offline toggle's readiness gate. With no enabled variant there is nothing to play
+ * offline, so it is never ready. The fetch is not aborted on a timeout; it keeps warming the
+ * on-device cache in the background so a later flip to offline succeeds immediately.
+ */
+export async function ensureOfflineDicts(prof: Profile, budgetMs: number): Promise<boolean> {
+  if (prof.variantPreferences.length === 0) return false;
+  const run = preloadDicts(prof.dictVersions, prof.variantPreferences, {
+    getDawg,
+    disabled: dictLoadingDisabled,
+    retries: 1,
+  });
+  return raceOfflineReady(run, budgetMs);
+}

ui/src/lib/dict/preload.test.ts

@@ -0,0 +1,86 @@
+import { describe, it, expect } from 'vitest';
+import { preloadDicts } from './preload';
+import type { Variant } from '../model';
+import type { Dawg } from './dawg';
+
+// A non-null stand-in for a loaded reader — preloadDicts only checks getDawg's result for null.
+const DAWG = {} as Dawg;
+const noSleep = (): Promise<void> => Promise.resolve();
+
+describe('preloadDicts', () => {
+  it('fetches every enabled variant that has a known version', async () => {
+    const calls: string[] = [];
+    const res = await preloadDicts({ scrabble_en: 'v1', scrabble_ru: 'v2', erudit_ru: 'v3' }, ['scrabble_en', 'erudit_ru'], {
+      getDawg: async (v: Variant, ver: string) => {
+        calls.push(`${v}@${ver}`);
+        return DAWG;
+      },
+      disabled: () => false,
+      sleep: noSleep,
+    });
+    expect(res.ok).toEqual(['scrabble_en', 'erudit_ru']);
+    expect(res.failed).toEqual([]);
+    expect(calls).toEqual(['scrabble_en@v1', 'erudit_ru@v3']);
+  });
+
+  it('marks a variant with no known version as failed without fetching it', async () => {
+    const calls: string[] = [];
+    const res = await preloadDicts({ scrabble_en: 'v1' }, ['scrabble_en', 'scrabble_ru'], {
+      getDawg: async (v: Variant) => {
+        calls.push(v);
+        return DAWG;
+      },
+      disabled: () => false,
+      sleep: noSleep,
+    });
+    expect(res.ok).toEqual(['scrabble_en']);
+    expect(res.failed).toEqual(['scrabble_ru']);
+    expect(calls).toEqual(['scrabble_en']);
+  });
+
+  it('retries a transient failure with linear backoff, then succeeds', async () => {
+    let attempts = 0;
+    const waits: number[] = [];
+    const res = await preloadDicts({ scrabble_en: 'v1' }, ['scrabble_en'], {
+      getDawg: async () => (++attempts >= 3 ? DAWG : null),
+      disabled: () => false,
+      sleep: async (ms: number) => void waits.push(ms),
+      retries: 3,
+      backoffMs: 100,
+    });
+    expect(res.ok).toEqual(['scrabble_en']);
+    expect(attempts).toBe(3);
+    expect(waits).toEqual([100, 200]);
+  });
+
+  it('gives up a persistent failure after the retry budget', async () => {
+    let attempts = 0;
+    const res = await preloadDicts({ scrabble_en: 'v1' }, ['scrabble_en'], {
+      getDawg: async () => {
+        attempts++;
+        return null;
+      },
+      disabled: () => false,
+      sleep: noSleep,
+      retries: 2,
+    });
+    expect(res.failed).toEqual(['scrabble_en']);
+    expect(res.ok).toEqual([]);
+    expect(attempts).toBe(3);
+  });
+
+  it('stops retrying once the session miss-breaker trips', async () => {
+    let attempts = 0;
+    const res = await preloadDicts({ scrabble_en: 'v1' }, ['scrabble_en'], {
+      getDawg: async () => {
+        attempts++;
+        return null;
+      },
+      disabled: () => true,
+      sleep: noSleep,
+      retries: 5,
+    });
+    expect(res.failed).toEqual(['scrabble_en']);
+    expect(attempts).toBe(1);
+  });
+});

ui/src/lib/dict/preload.ts

@@ -0,0 +1,68 @@
+// Background dictionary preload for offline readiness. An installed PWA with a confirmed email
+// warms the dictionaries for the player's enabled variants while online, so a later switch to
+// deliberate offline mode has the data it needs. The pure preloadDicts here takes its side effects
+// (getDawg, the session miss-breaker, sleep) as dependencies, so it unit-tests in the node env. The
+// eligibility and once/online guard live in offline.svelte.ts (kickDictPreload); the browser
+// orchestration that supplies the real side effects and raises the in-lobby warning lives in
+// preloadrun.ts, which offline.svelte.ts imports dynamically so neither the loader nor the
+// generator is pulled into the main bundle.
+
+import type { Variant } from '../model';
+import type { Dawg } from './dawg';
+
+/** PreloadDeps injects preloadDicts's side effects so the logic stays pure and testable. */
+export interface PreloadDeps {
+  /** getDawg resolves the (variant, version) reader, serving memory/IndexedDB before the network,
+   *  or null on any miss — mirrors the in-game loader. */
+  getDawg: (variant: Variant, version: string) => Promise<Dawg | null>;
+  /** disabled reports whether the session dictionary miss-breaker has tripped (too many network
+   *  misses this session); when it has, a network fetch will not recover, so retries stop. */
+  disabled: () => boolean;
+  /** sleep waits between retries; defaults to a real timer. */
+  sleep?: (ms: number) => Promise<void>;
+  /** retries is the number of extra attempts after the first (default 2). */
+  retries?: number;
+  /** backoffMs is the base linear backoff between attempts (default 800). */
+  backoffMs?: number;
+}
+
+/** PreloadResult reports which enabled variants ended up available (ok) and which are still
+ *  missing (failed) after the preload — the caller surfaces a warning when failed is non-empty. */
+export interface PreloadResult {
+  ok: Variant[];
+  failed: Variant[];
+}
+
+/**
+ * preloadDicts fetches, via getDawg, the dictionary for each enabled variant that has a known
+ * version, retrying transient misses with linear backoff. A variant with no known version, or one
+ * still missing after the retry budget, lands in failed; the rest in ok. It never throws and stops
+ * retrying a variant once the session miss-breaker (disabled) trips, since the network will not
+ * recover this session — a cached dictionary is still served by getDawg regardless.
+ */
+export async function preloadDicts(
+  versions: Partial<Record<Variant, string>>,
+  enabled: readonly Variant[],
+  deps: PreloadDeps,
+): Promise<PreloadResult> {
+  const sleep = deps.sleep ?? ((ms) => new Promise<void>((r) => setTimeout(r, ms)));
+  const retries = deps.retries ?? 2;
+  const backoffMs = deps.backoffMs ?? 800;
+  const ok: Variant[] = [];
+  const failed: Variant[] = [];
+  for (const variant of enabled) {
+    const version = versions[variant];
+    if (!version) {
+      failed.push(variant);
+      continue;
+    }
+    let dawg: Dawg | null = null;
+    for (let attempt = 0; attempt <= retries; attempt++) {
+      dawg = await deps.getDawg(variant, version);
+      if (dawg || deps.disabled()) break;
+      if (attempt < retries) await sleep(backoffMs * (attempt + 1));
+    }
+    (dawg ? ok : failed).push(variant);
+  }
+  return { ok, failed };
+}

ui/src/lib/dict/preloadrun.ts

@@ -0,0 +1,24 @@
+// Browser-only orchestration for the offline dictionary preload. Kept apart from the pure
+// preloadDicts (preload.ts) — which unit-tests in the node env — and lazily imported by
+// offline.svelte.ts's kickDictPreload, so the dict loader/generator it pulls in stays out of the
+// main bundle. It supplies the real side effects (getDawg, the session miss-breaker) and raises the
+// in-lobby notice when a first-lobby preload cannot fetch every enabled variant's dictionary.
+
+import type { Profile } from '../model';
+import { preloadDicts } from './preload';
+import { getDawg, dictLoadingDisabled } from '../dict';
+import { setDictPreloadWarning } from '../offline.svelte';
+
+/**
+ * runPreload warms the dictionaries for the profile's enabled variants (using the versions the
+ * profile advertises) via the real dict loader, so a later switch to offline mode has the data.
+ * When warnOnFail is set (the first lobby entry), it raises the in-lobby notice if a variant is
+ * still missing afterwards, and clears it on a run where every variant is available.
+ */
+export async function runPreload(prof: Profile, warnOnFail: boolean): Promise<void> {
+  const res = await preloadDicts(prof.dictVersions, prof.variantPreferences, {
+    getDawg,
+    disabled: dictLoadingDisabled,
+  });
+  if (warnOnFail) setDictPreloadWarning(res.failed.length > 0);
+}

ui/src/lib/dict/testdata/sample_en.words.json

@@ -0,0 +1,122 @@
+{
+  "alphabet": "en",
+  "numAdded": 18,
+  "words": [
+    "a",
+    "an",
+    "and",
+    "ant",
+    "car",
+    "care",
+    "cared",
+    "cares",
+    "cars",
+    "cat",
+    "cats",
+    "do",
+    "doe",
+    "does",
+    "dog",
+    "dogs",
+    "done",
+    "dot"
+  ],
+  "indexes": [
+    [
+      0
+    ],
+    [
+      0,
+      13
+    ],
+    [
+      0,
+      13,
+      3
+    ],
+    [
+      0,
+      13,
+      19
+    ],
+    [
+      2,
+      0,
+      17
+    ],
+    [
+      2,
+      0,
+      17,
+      4
+    ],
+    [
+      2,
+      0,
+      17,
+      4,
+      3
+    ],
+    [
+      2,
+      0,
+      17,
+      4,
+      18
+    ],
+    [
+      2,
+      0,
+      17,
+      18
+    ],
+    [
+      2,
+      0,
+      19
+    ],
+    [
+      2,
+      0,
+      19,
+      18
+    ],
+    [
+      3,
+      14
+    ],
+    [
+      3,
+      14,
+      4
+    ],
+    [
+      3,
+      14,
+      4,
+      18
+    ],
+    [
+      3,
+      14,
+      6
+    ],
+    [
+      3,
+      14,
+      6,
+      18
+    ],
+    [
+      3,
+      14,
+      13,
+      4
+    ],
+    [
+      3,
+      14,
+      19
+    ]
+  ]
+}

ui/src/lib/dict/testdata/sample_ru.words.json

@@ -0,0 +1,38 @@
+{
+  "alphabet": "ru",
+  "numAdded": 6,
+  "words": [
+    "ад",
+    "ар",
+    "оса",
+    "я",
+    "яд",
+    "яр"
+  ],
+  "indexes": [
+    [
+      0,
+      4
+    ],
+    [
+      0,
+      17
+    ],
+    [
+      15,
+      18,
+      0
+    ],
+    [
+      32
+    ],
+    [
+      32,
+      4
+    ],
+    [
+      32,
+      17
+    ]
+  ]
+}

ui/src/lib/dict/validate.ts

@@ -297,8 +297,9 @@ export function validatePlay(
 }
 
 // connected reports whether the play connects to the position (or covers the
-// centre on the first move). Mirrors (*Solver).connected.
+// centre on the first move). Mirrors (*Solver).connected. Exported so the move
-function connected(b: Board, rs: Ruleset, m: Move): boolean {
+// generator can apply the same post-generation connectivity filter.
+export function connected(b: Board, rs: Ruleset, m: Move): boolean {
   if (b.isEmpty()) {
     const cr = Math.floor(rs.center / rs.cols);
     const cc = rs.center % rs.cols;

ui/src/lib/gamesource.ts

@@ -0,0 +1,76 @@
+// Dispatch a game id to its source: the local engine (an offline vs_ai game) or the network
+// gateway. The same game screen (game/Game.svelte) drives both through the shared game-loop subset
+// (GameLoopSource); a game id decides which. A network game's calls are unchanged — gameSource
+// returns the gateway itself for it — so the seam adds the local path without touching online play.
+//
+// The offline engine is kept OUT of the app entry bundle: this module statically imports only the
+// gateway, the tiny id helper and types; the LocalSource is dynamically imported on first use of a
+// local game, so it loads as a separate chunk only when someone plays offline.
+
+import { gateway } from './gateway';
+import { isLocalGameId } from './localgame/id';
+import type { GameLoopSource, LocalSource } from './localgame/source';
+
+let loaded: Promise<LocalSource> | null = null;
+function load(): Promise<LocalSource> {
+  if (!loaded) loaded = import('./localgame/source').then((m) => new m.LocalSource());
+  return loaded;
+}
+
+/**
+ * localSource is a lazy handle on the single offline LocalSource. It is obtainable synchronously,
+ * but each method dynamically imports the engine on first use, so the offline code stays out of the
+ * app entry bundle until a local game is actually played. It exposes the game-loop methods plus the
+ * local-only create() and the robot-reply event subscription events().
+ */
+export const localSource = {
+  // Offline scoring is self-contained, so the local source ignores includeAlphabet, the evaluate
+  // abort signal, and the draft (drafts are not persisted offline); the proxy accepts the full
+  // gateway signatures but forwards only what the local source uses.
+  gameState: (id, _includeAlphabet) => load().then((s) => s.gameState(id)),
+  gameHistory: (id) => load().then((s) => s.gameHistory(id)),
+  submitPlay: (id, tiles, variant) => load().then((s) => s.submitPlay(id, tiles, variant)),
+  pass: (id) => load().then((s) => s.pass(id)),
+  exchange: (id, tiles, variant) => load().then((s) => s.exchange(id, tiles, variant)),
+  resign: (id) => load().then((s) => s.resign(id)),
+  hint: (id) => load().then((s) => s.hint(id)),
+  evaluate: (id, tiles, variant, _signal) => load().then((s) => s.evaluate(id, tiles, variant)),
+  checkWord: (id, word, variant) => load().then((s) => s.checkWord(id, word, variant)),
+  draftGet: (_id) => load().then((s) => s.draftGet()),
+  draftSave: (_id, _json) => load().then((s) => s.draftSave()),
+  create: (opts) => load().then((s) => s.create(opts)),
+  list: () => load().then((s) => s.list()),
+  delete: (id) => load().then((s) => s.delete(id)),
+  // Offline hotseat controls (no network equivalent): reveal a PIN-locked seat, and the host
+  // (referee) overrides gated by the master PIN.
+  unlockSeat: (id, pin) => load().then((s) => s.unlockSeat(id, pin)),
+  verifyHostPin: (id, pin) => load().then((s) => s.verifyHostPin(id, pin)),
+  hostAction: (id, pin, action, targetSeat) => load().then((s) => s.hostAction(id, pin, action, targetSeat)),
+  // relock is fire-and-forget: the engine is already loaded (the game was open), and re-locking a
+  // cached game before the screen is left needs no result.
+  relock: (id) => void load().then((s) => s.relock(id)),
+  // events must return the unsubscribe synchronously (the screen subscribes in onMount), so it wires
+  // the real subscription once the engine loads and, until then, cancels a pending subscribe.
+  events: (id, onEvent) => {
+    let unsub = (): void => {};
+    let cancelled = false;
+    void load().then((s) => {
+      if (!cancelled) unsub = s.events(id, onEvent);
+    });
+    return () => {
+      cancelled = true;
+      unsub();
+    };
+  },
+} satisfies GameLoopSource &
+  Pick<LocalSource, 'events' | 'create' | 'list' | 'delete' | 'unlockSeat' | 'verifyHostPin' | 'hostAction' | 'relock'>;
+
+/**
+ * gameSource returns the source that runs the game with the given id: the local engine for a local
+ * id, otherwise the network gateway (which satisfies the same game-loop interface).
+ */
+export function gameSource(id: string): GameLoopSource {
+  return isLocalGameId(id) ? localSource : gateway;
+}
+
+export { isLocalGameId } from './localgame/id';

ui/src/lib/gateway.ts

@@ -5,6 +5,7 @@
 import type { GatewayClient } from './client';
 import { MockGateway } from './mock/client';
 import { createTransport } from './transport';
+import { setForcedSeed } from './localgame/id';
 import { reportOffline, reportOnline } from './connection.svelte';
 import { clearMaintenance, maintenanceRecovered, reportMaintenance } from './maintenance.svelte';
 
@@ -41,6 +42,7 @@ if (isMock && typeof window !== 'undefined') {
         setGameLimit(v: boolean): void;
         clearEmail(): void;
         confirmEmailOutOfBand(email: string): void;
+        setLocalSeed(seed: string): void;
       };
     }
   ).__mock = {
@@ -50,5 +52,8 @@ if (isMock && typeof window !== 'undefined') {
     setGameLimit: (v: boolean) => (gateway as MockGateway).setGameLimit(v),
     clearEmail: () => (gateway as MockGateway).mockClearEmail(),
     confirmEmailOutOfBand: (email: string) => (gateway as MockGateway).mockConfirmEmailOutOfBand(email),
+    // Pin the next local game's bag seed, so the offline e2e deals a known rack (a bigint as a
+    // string — window hooks marshal strings cleanly).
+    setLocalSeed: (seed: string) => setForcedSeed(BigInt(seed)),
   };
 }

ui/src/lib/hints.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest';
-import { hintsLeft } from './hints';
+import { hintsLeft, hintGateRemainingMs, hintLockMinutes } from './hints';
 
 // view carries only the two fields hintsLeft reads.
 const view = (hintsRemaining: number, walletBalance: number) => ({ hintsRemaining, walletBalance });
@@ -30,3 +30,32 @@ describe('hintsLeft', () => {
     expect(hintsLeft(view(1, 0), -5)).toBe(1);
   });
 });
+
+describe('hintGateRemainingMs (the vs_ai idle-hint gate, monotonic)', () => {
+  it('is 0 when the gate is open — a null anchor (the human first move, or a non-gated game)', () => {
+    expect(hintGateRemainingMs(null, 60_000, 5000)).toBe(0);
+  });
+
+  it('is the window remaining minus the monotonic time elapsed since the anchor', () => {
+    // anchored at mono 1000 with 60s left; 20s of monotonic time later -> 40s left.
+    expect(hintGateRemainingMs(1000, 60_000, 1000 + 20_000)).toBe(40_000);
+  });
+
+  it('is 0 once the elapsed monotonic time reaches (or passes) the window', () => {
+    expect(hintGateRemainingMs(1000, 60_000, 1000 + 60_000)).toBe(0);
+    expect(hintGateRemainingMs(1000, 60_000, 1000 + 90_000)).toBe(0);
+  });
+});
+
+describe('hintLockMinutes (the toast N, rounded up)', () => {
+  it('rounds up to whole minutes, so a still-closed gate never reads 0', () => {
+    expect(hintLockMinutes(1)).toBe(1);
+    expect(hintLockMinutes(60_000)).toBe(1);
+    expect(hintLockMinutes(61_000)).toBe(2);
+    expect(hintLockMinutes(29 * 60_000)).toBe(29);
+  });
+
+  it('is 0 when nothing remains', () => {
+    expect(hintLockMinutes(0)).toBe(0);
+  });
+});

ui/src/lib/hints.ts

@@ -24,3 +24,27 @@ export function hintsLeft(
   const allowance = Math.max(0, view.hintsRemaining - view.walletBalance);
   return allowance + Math.max(0, walletBalance);
 }
+
+/** HINT_GATE_MS is the idle time a vs_ai player must be stuck on a turn before a hint unlocks. */
+export const HINT_GATE_MS = 30 * 60 * 1000;
+
+/**
+ * hintGateRemainingMs returns how long (in milliseconds) until a vs_ai game's idle hint unlocks — 0
+ * once it is available. It counts down from a MONOTONIC clock (performance.now()), so a client clock
+ * change cannot skew it: gateStartMono is performance.now() captured when the source's "seconds left"
+ * was received, gateLeftMs is that seconds-left in ms, and monoNow is performance.now() now; the
+ * remaining is gateLeftMs minus the monotonic time elapsed since the anchor. gateStartMono null means
+ * the gate is open (the human's first move, or a non-gated game). The duration comes from the source
+ * (the SERVER clock online, the device clock offline) and is re-fetched on every load, so the wait
+ * both persists across a relaunch and stays immune to a live clock change.
+ */
+export function hintGateRemainingMs(gateStartMono: number | null, gateLeftMs: number, monoNow: number): number {
+  if (gateStartMono === null) return 0;
+  return Math.max(0, gateLeftMs - (monoNow - gateStartMono));
+}
+
+/** hintLockMinutes rounds a remaining-milliseconds gap up to whole minutes for the "available in N
+ *  min." toast, so a gate that is still closed never reads 0. */
+export function hintLockMinutes(remainingMs: number): number {
+  return Math.ceil(remainingMs / 60000);
+}

ui/src/lib/i18n/en.ts

@@ -99,6 +99,7 @@ export const en = {
   'game.draw': 'Exchange/Pass',
   'game.shuffle': 'Shuffle',
   'game.hint': 'Hint',
+  'game.hintLockedIn': 'Available in {n} min.',
   'game.chat': 'Chat',
   'game.checkWord': 'Check word',
   'game.dictionary': 'Dictionary',
@@ -214,6 +215,15 @@ export const en = {
   'settings.labelsClassic': 'Classic',
   'settings.labelsNone': 'None',
   'settings.reduceMotion': 'Reduce motion',
+  'settings.offlineMode': 'Play mode',
+  'settings.online': 'Online',
+  'settings.offline': 'Offline',
+  'settings.offlineChecking': 'Loading dictionaries…',
+  'settings.offlineNeedsData': 'Not enough data on the device. Internet access is needed to download it.',
+  'offline.preloadWarning': 'Poor internet connection. Some features may be unavailable.',
+  'offline.promptTitle': 'No connection. Enable offline mode?',
+  'offline.promptYes': 'Enable',
+  'offline.promptNo': 'Keep trying',
 
   'about.title': 'About',
   'about.tab': 'Info',
@@ -234,6 +244,17 @@ export const en = {
   'landing.tagline': 'Play Scrabble with friends, random opponent or an AI.',
   'landing.playTelegram': 'Play in Telegram',
   'landing.playVK': 'Play on VK',
+  'landing.playWeb': 'Play in your browser',
+  'landing.captionTelegram': 'Telegram',
+  'landing.captionVK': 'VK',
+  'landing.captionWeb': 'Web',
+
+  'install.title': 'Install the app',
+  'install.subtitle': 'Put the app icon on your desktop (home screen) to open the game in one tap.',
+  'install.iosTitle': 'Add to Home Screen',
+  'install.iosStep1': 'Tap the Share button in the browser toolbar.',
+  'install.iosStep2': 'Choose “Add to Home Screen”.',
+  'install.iosStep3': 'Tap “Add”.',
 
   'lang.en': 'English',
   'lang.ru': 'Русский',
@@ -368,6 +389,35 @@ export const en = {
   'error.game_active': 'Available only after the game is finished.',
   'error.invalid_profile': 'Some profile fields are invalid.',
   'error.already_confirmed': 'This email is already confirmed.',
+
+  'pin.enter': 'Enter PIN',
+  'pin.create': 'Create a PIN',
+  'pin.repeat': 'Repeat the PIN',
+  'pin.enterCurrent': 'Enter current PIN',
+  'pin.mismatch': "PINs don't match",
+  'pin.wrong': 'Wrong PIN',
+  'pin.setNew': 'Set a new PIN',
+  'pin.remove': 'Remove PIN',
+
+  'hotseat.hostPin': 'Host password',
+  'hotseat.setPin': 'Password',
+  'hotseat.changePin': 'Change',
+  'hotseat.playerName': 'Player name',
+  'hotseat.addPlayer': 'Add player',
+  'hotseat.removePlayer': 'Remove player',
+  'hotseat.hostPlaysTitle': 'Are you playing too?',
+  'hotseat.hostPlaysYes': 'Yes, I play',
+  'hotseat.hostPlaysNo': 'No',
+  'hotseat.unlock': 'Unlock',
+  'hotseat.unlockTitle': 'Unlock: {name}',
+  'hotseat.turnOf': 'Turn: {name}',
+  'hotseat.host': 'Host',
+  'hotseat.skip': 'Skip the current turn',
+  'hotseat.exclude': 'Exclude a player:',
+  'hotseat.terminate': 'End the game',
+  'hotseat.askSkip': "Skip {name}'s turn?",
+  'hotseat.askExclude': 'Remove {name} from the game?',
+  'hotseat.askTerminate': 'End the game with no result?',
 } as const;
 
 export type MessageKey = keyof typeof en;

ui/src/lib/i18n/ru.ts

@@ -99,6 +99,7 @@ export const ru: Record<MessageKey, string> = {
   'game.draw': 'Обмен/Пас',
   'game.shuffle': 'Перемешать',
   'game.hint': 'Подсказка',
+  'game.hintLockedIn': 'Будет доступно через {n} мин.',
   'game.chat': 'Чат',
   'game.checkWord': 'Проверить слово',
   'game.dictionary': 'Словарь',
@@ -214,6 +215,15 @@ export const ru: Record<MessageKey, string> = {
   'settings.labelsClassic': 'Классика',
   'settings.labelsNone': 'Без текста',
   'settings.reduceMotion': 'Меньше анимаций',
+  'settings.offlineMode': 'Режим игры',
+  'settings.online': 'Онлайн',
+  'settings.offline': 'Оффлайн',
+  'settings.offlineChecking': 'Загрузка словарей…',
+  'settings.offlineNeedsData': 'Недостаточно данных. Необходим доступ в интернет для загрузки.',
+  'offline.preloadWarning': 'Плохое соединение с интернет. Некоторые функции могут быть недоступны.',
+  'offline.promptTitle': 'Нет связи. Включить офлайн-режим?',
+  'offline.promptYes': 'Включить',
+  'offline.promptNo': 'Ждать сеть',
 
   'about.title': 'О программе',
   'about.tab': 'Инфо',
@@ -234,6 +244,17 @@ export const ru: Record<MessageKey, string> = {
   'landing.tagline': 'Играй в «Эрудита» с друзьями, случайным соперником или ИИ-роботом.',
   'landing.playTelegram': 'Играть в Telegram',
   'landing.playVK': 'Играть во ВКонтакте',
+  'landing.playWeb': 'Играть в браузере',
+  'landing.captionTelegram': 'Telegram',
+  'landing.captionVK': 'VK',
+  'landing.captionWeb': 'Веб-версия',
+
+  'install.title': 'Установить приложение',
+  'install.subtitle': 'Поместите иконку приложения на рабочий стол (домашний экран), чтобы открывать игру одним нажатием.',
+  'install.iosTitle': 'На экран «Домой»',
+  'install.iosStep1': 'Нажмите кнопку «Поделиться» на панели браузера.',
+  'install.iosStep2': 'Выберите «На экран „Домой“».',
+  'install.iosStep3': 'Нажмите «Добавить».',
 
   'lang.en': 'English',
   'lang.ru': 'Русский',
@@ -368,4 +389,33 @@ export const ru: Record<MessageKey, string> = {
   'error.game_active': 'Доступно только после завершения игры.',
   'error.invalid_profile': 'Некоторые поля профиля некорректны.',
   'error.already_confirmed': 'Эта почта уже подтверждена.',
+
+  'pin.enter': 'Введите PIN',
+  'pin.create': 'Придумайте PIN',
+  'pin.repeat': 'Повторите PIN',
+  'pin.enterCurrent': 'Введите текущий PIN',
+  'pin.mismatch': 'PIN не совпадает',
+  'pin.wrong': 'Неверный PIN',
+  'pin.setNew': 'Задать новый PIN',
+  'pin.remove': 'Удалить пароль',
+
+  'hotseat.hostPin': 'Пароль ведущего',
+  'hotseat.setPin': 'Пароль',
+  'hotseat.changePin': 'Изменить',
+  'hotseat.playerName': 'Имя игрока',
+  'hotseat.addPlayer': 'Добавить игрока',
+  'hotseat.removePlayer': 'Удалить игрока',
+  'hotseat.hostPlaysTitle': 'Принимаете участие в игре?',
+  'hotseat.hostPlaysYes': 'Да, играю',
+  'hotseat.hostPlaysNo': 'Нет',
+  'hotseat.unlock': 'Разблокировать',
+  'hotseat.unlockTitle': 'Разблокировать: {name}',
+  'hotseat.turnOf': 'Ход: {name}',
+  'hotseat.host': 'Ведущий',
+  'hotseat.skip': 'Пропустить ход',
+  'hotseat.exclude': 'Исключить игрока:',
+  'hotseat.terminate': 'Отменить партию',
+  'hotseat.askSkip': 'Пропустить ход игрока {name}?',
+  'hotseat.askExclude': 'Удалить {name} из игры?',
+  'hotseat.askTerminate': 'Отменить партию без результата?',
 };

ui/src/lib/lobbycache.test.ts

@@ -43,10 +43,10 @@ beforeEach(() => clearLobby());
 
 describe('patchLobbyGame', () => {
   it('replaces the matching game by id and leaves the others untouched', () => {
-    setLobby({ games: [gameView('a', 'active', 0), gameView('b', 'active', 0)], invitations: [], incoming: [], atGameLimit: false });
+    setLobby({ games: [gameView('a', 'active', 0), gameView('b', 'active', 0)], invitations: [], incoming: [], atGameLimit: false, offline: false });
     // The player's own move flipped game "a" to the opponent's turn.
     patchLobbyGame(gameView('a', 'active', 1));
-    const snap = getLobby();
+    const snap = getLobby(false);
     expect(snap?.games.map((g) => g.id)).toEqual(['a', 'b']);
     expect(snap?.games.find((g) => g.id === 'a')?.toMove).toBe(1);
     expect(snap?.games.find((g) => g.id === 'b')?.toMove).toBe(0);
@@ -54,27 +54,27 @@ describe('patchLobbyGame', () => {
 
   it('preserves invitations and incoming when patching a game', () => {
     const incoming: AccountRef[] = [{ accountId: 'u9', displayName: 'Nine' }];
-    setLobby({ games: [gameView('a')], invitations: [], incoming, atGameLimit: false });
+    setLobby({ games: [gameView('a')], invitations: [], incoming, atGameLimit: false, offline: false });
     patchLobbyGame(gameView('a', 'finished'));
-    expect(getLobby()?.incoming).toEqual(incoming);
+    expect(getLobby(false)?.incoming).toEqual(incoming);
-    expect(getLobby()?.games[0].status).toBe('finished');
+    expect(getLobby(false)?.games[0].status).toBe('finished');
   });
 
   it('adds the game when it is not yet in the cached lobby (a game started elsewhere)', () => {
-    setLobby({ games: [gameView('a')], invitations: [], incoming: [], atGameLimit: false });
+    setLobby({ games: [gameView('a')], invitations: [], incoming: [], atGameLimit: false, offline: false });
     patchLobbyGame(gameView('z', 'active'));
     // Order is irrelevant — the lobby re-groups and re-sorts on render — so assert membership.
-    expect(getLobby()?.games.map((g) => g.id).sort()).toEqual(['a', 'z']);
+    expect(getLobby(false)?.games.map((g) => g.id).sort()).toEqual(['a', 'z']);
   });
 
   it('is a no-op when there is no cached lobby yet', () => {
     patchLobbyGame(gameView('a'));
-    expect(getLobby()).toBeNull();
+    expect(getLobby(false)).toBeNull();
   });
 
   it('does not mutate the previous snapshot array', () => {
     const games = [gameView('a', 'active', 0)];
-    setLobby({ games, invitations: [], incoming: [], atGameLimit: false });
+    setLobby({ games, invitations: [], incoming: [], atGameLimit: false, offline: false });
     patchLobbyGame(gameView('a', 'active', 1));
     expect(games[0].toMove).toBe(0); // the original array/object is left intact
   });
@@ -82,51 +82,67 @@ describe('patchLobbyGame', () => {
   it('preserves the at-game-limit flag across a game patch', () => {
     // A finished-game patch arriving while the lobby is unmounted must not drop the flag —
     // the lobby renders the "New Game" button from the cached snapshot before the refresh.
-    setLobby({ games: [gameView('a')], invitations: [], incoming: [], atGameLimit: true });
+    setLobby({ games: [gameView('a')], invitations: [], incoming: [], atGameLimit: true, offline: false });
     patchLobbyGame(gameView('a', 'finished'));
-    expect(getLobby()?.atGameLimit).toBe(true);
+    expect(getLobby(false)?.atGameLimit).toBe(true);
   });
 });
 
 describe('patchLobbyInvitation', () => {
   it('adds a new pending invitation to the cached lobby', () => {
-    setLobby({ games: [], invitations: [], incoming: [], atGameLimit: false });
+    setLobby({ games: [], invitations: [], incoming: [], atGameLimit: false, offline: false });
     patchLobbyInvitation(invitation('i1', 'pending'));
-    expect(getLobby()?.invitations.map((x) => x.id)).toEqual(['i1']);
+    expect(getLobby(false)?.invitations.map((x) => x.id)).toEqual(['i1']);
   });
 
   it('replaces a pending invitation already in the list (e.g. an updated response)', () => {
-    setLobby({ games: [], invitations: [invitation('i1', 'pending'), invitation('i2', 'pending')], incoming: [], atGameLimit: false });
+    setLobby({ games: [], invitations: [invitation('i1', 'pending'), invitation('i2', 'pending')], incoming: [], atGameLimit: false, offline: false });
     const updated = { ...invitation('i1', 'pending'), turnTimeoutSecs: 999 };
     patchLobbyInvitation(updated);
-    expect(getLobby()?.invitations.map((x) => x.id)).toEqual(['i1', 'i2']);
+    expect(getLobby(false)?.invitations.map((x) => x.id)).toEqual(['i1', 'i2']);
-    expect(getLobby()?.invitations.find((x) => x.id === 'i1')?.turnTimeoutSecs).toBe(999);
+    expect(getLobby(false)?.invitations.find((x) => x.id === 'i1')?.turnTimeoutSecs).toBe(999);
   });
 
   it('removes an invitation that reached a terminal status', () => {
     for (const terminal of ['declined', 'cancelled', 'started', 'expired']) {
-      setLobby({ games: [], invitations: [invitation('i1', 'pending'), invitation('i2', 'pending')], incoming: [], atGameLimit: false });
+      setLobby({ games: [], invitations: [invitation('i1', 'pending'), invitation('i2', 'pending')], incoming: [], atGameLimit: false, offline: false });
       patchLobbyInvitation(invitation('i1', terminal));
-      expect(getLobby()?.invitations.map((x) => x.id)).toEqual(['i2']);
+      expect(getLobby(false)?.invitations.map((x) => x.id)).toEqual(['i2']);
     }
   });
 
   it('is a no-op for a terminal invitation that is not in the list', () => {
-    setLobby({ games: [], invitations: [invitation('i2', 'pending')], incoming: [], atGameLimit: false });
+    setLobby({ games: [], invitations: [invitation('i2', 'pending')], incoming: [], atGameLimit: false, offline: false });
     patchLobbyInvitation(invitation('i1', 'declined'));
-    expect(getLobby()?.invitations.map((x) => x.id)).toEqual(['i2']);
+    expect(getLobby(false)?.invitations.map((x) => x.id)).toEqual(['i2']);
   });
 
   it('is a no-op when there is no cached lobby yet', () => {
     patchLobbyInvitation(invitation('i1', 'pending'));
-    expect(getLobby()).toBeNull();
+    expect(getLobby(false)).toBeNull();
   });
 
   it('preserves games and incoming when patching an invitation', () => {
     const incoming: AccountRef[] = [{ accountId: 'u9', displayName: 'Nine' }];
-    setLobby({ games: [gameView('g1')], invitations: [], incoming, atGameLimit: false });
+    setLobby({ games: [gameView('g1')], invitations: [], incoming, atGameLimit: false, offline: false });
     patchLobbyInvitation(invitation('i1', 'pending'));
-    expect(getLobby()?.games.map((g) => g.id)).toEqual(['g1']);
+    expect(getLobby(false)?.games.map((g) => g.id)).toEqual(['g1']);
-    expect(getLobby()?.incoming).toEqual(incoming);
+    expect(getLobby(false)?.incoming).toEqual(incoming);
+  });
+});
+
+describe('getLobby is mode-aware (a mode flip must not render the other mode’s games)', () => {
+  it('returns the snapshot only for the mode it was stored under', () => {
+    setLobby({ games: [gameView('online1')], invitations: [], incoming: [], atGameLimit: false, offline: false });
+    expect(getLobby(false)?.games.map((g) => g.id)).toEqual(['online1']);
+    // Reading it as the OTHER (offline) mode must not surface the online snapshot.
+    expect(getLobby(true)).toBeNull();
+  });
+
+  it('replaces the snapshot when the mode changes, so the stale mode is dropped', () => {
+    setLobby({ games: [gameView('online1')], invitations: [], incoming: [], atGameLimit: false, offline: false });
+    setLobby({ games: [gameView('local1')], invitations: [], incoming: [], atGameLimit: false, offline: true });
+    expect(getLobby(false)).toBeNull();
+    expect(getLobby(true)?.games.map((g) => g.id)).toEqual(['local1']);
   });
 });

ui/src/lib/lobbycache.ts

@@ -13,13 +13,18 @@ interface LobbySnapshot {
   // atGameLimit rides the snapshot so the lobby renders the "New Game" button in its last
   // known enabled/disabled state instantly (no flicker), then refreshes it in the background.
   atGameLimit: boolean;
+  // Which mode the snapshot belongs to (offline = device-local games, online = server games). The
+  // lobby renders it instantly only when it matches the current mode, so a mode flip never flashes —
+  // or lets the player open — the other mode's games before the background refresh replaces them.
+  offline: boolean;
 }
 
 let snapshot: LobbySnapshot | null = null;
 
-/** getLobby returns the last lobby lists, or null before the first load. */
+/** getLobby returns the last lobby lists for the given mode, or null before the first load or when
-export function getLobby(): LobbySnapshot | null {
+ *  the cached snapshot belongs to the other mode (so the lobby cold-renders after a mode flip). */
-  return snapshot;
+export function getLobby(offline: boolean): LobbySnapshot | null {
+  return snapshot && snapshot.offline === offline ? snapshot : null;
 }
 
 /** setLobby stores the latest lobby lists. */

ui/src/lib/localgame/bag.test.ts

@@ -0,0 +1,50 @@
+import { describe, it, expect } from 'vitest';
+import { Bag } from './bag';
+import { RULESETS } from './ruleset';
+import { BLANK_INDEX } from '../alphabet';
+
+describe('offline bag', () => {
+  it('holds exactly the variant tile distribution', () => {
+    const rs = RULESETS.scrabble_en;
+    const total = rs.counts.reduce((a, b) => a + b, 0) + rs.blanks;
+    const bag = new Bag('scrabble_en', 42);
+    expect(bag.length).toBe(total);
+
+    const drawn = bag.draw(total);
+    expect(drawn.length).toBe(total);
+    expect(bag.length).toBe(0);
+
+    const tally = new Map<number, number>();
+    for (const t of drawn) tally.set(t, (tally.get(t) ?? 0) + 1);
+    for (let i = 0; i < rs.counts.length; i++) expect(tally.get(i) ?? 0).toBe(rs.counts[i]);
+    expect(tally.get(BLANK_INDEX) ?? 0).toBe(rs.blanks);
+  });
+
+  it('draws beyond the remaining, returning all and emptying', () => {
+    const bag = new Bag('scrabble_ru', 7);
+    const total = bag.length;
+    const all = bag.draw(total + 5);
+    expect(all.length).toBe(total);
+    expect(bag.length).toBe(0);
+    expect(bag.draw(3)).toEqual([]);
+  });
+
+  it('returns tiles back to the bag', () => {
+    const bag = new Bag('erudit_ru', 1);
+    const before = bag.length;
+    const seven = bag.draw(7);
+    expect(bag.length).toBe(before - 7);
+    bag.return(seven);
+    expect(bag.length).toBe(before);
+  });
+
+  it('is deterministic for a given seed and operation sequence', () => {
+    const a = new Bag('scrabble_en', 123);
+    const b = new Bag('scrabble_en', 123);
+    expect(a.draw(30)).toEqual(b.draw(30));
+    // A return reshuffles both identically, so subsequent draws still agree.
+    a.return([0, 1, 2]);
+    b.return([0, 1, 2]);
+    expect(a.draw(10)).toEqual(b.draw(10));
+  });
+});

ui/src/lib/localgame/bag.ts

@@ -0,0 +1,76 @@
+// The offline tile bag — the shuffled draw pile for one local game. Structurally a port of
+// backend/internal/engine/bag.go (fill from the variant's counts + blanks, draw from the end,
+// return-and-reshuffle for an exchange), but shuffled with a small DETERMINISTIC in-house PRNG
+// rather than Go's math/rand: a local game only needs to be reproducible from its own seed and
+// sequence of operations (for replay from the stored journal), not bit-identical to a server
+// game (docs plan). Blanks ride as BLANK_INDEX, matching lib/alphabet.ts (and the engine's
+// blankTile = 0xff = 255).
+
+import { RULESETS } from './ruleset';
+import { BLANK_INDEX } from '../alphabet';
+import type { Variant } from '../model';
+
+// mulberry32 is a compact deterministic PRNG returning a float in [0, 1). Seeded from the game
+// seed so the shuffle sequence — and thus the draws — replay identically for the same seed and
+// the same sequence of returns.
+function mulberry32(seed: number): () => number {
+  let a = seed >>> 0;
+  return () => {
+    a = (a + 0x6d2b79f5) | 0;
+    let t = Math.imul(a ^ (a >>> 15), 1 | a);
+    t = (t + Math.imul(t ^ (t >>> 7), 61 | t)) ^ t;
+    return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
+  };
+}
+
+/**
+ * Bag is one local game's draw pile. Construct it with the variant and a numeric seed; draw()
+ * and return() mutate it in place. It is reproducible: the same seed and the same sequence of
+ * operations yield the same draws.
+ */
+export class Bag {
+  private tiles: number[];
+  private readonly rand: () => number;
+
+  constructor(variant: Variant, seed: number) {
+    const rs = RULESETS[variant];
+    const tiles: number[] = [];
+    for (let i = 0; i < rs.counts.length; i++) {
+      for (let n = 0; n < rs.counts[i]; n++) tiles.push(i);
+    }
+    for (let n = 0; n < rs.blanks; n++) tiles.push(BLANK_INDEX);
+    this.tiles = tiles;
+    this.rand = mulberry32(seed);
+    this.shuffle();
+  }
+
+  /** length is the number of tiles left in the bag. */
+  get length(): number {
+    return this.tiles.length;
+  }
+
+  /**
+   * draw removes up to n tiles from the end of the bag and returns them. Drawing more than
+   * remain returns all of them; drawing from an empty bag returns an empty array.
+   */
+  draw(n: number): number[] {
+    const take = Math.min(n, this.tiles.length);
+    return this.tiles.splice(this.tiles.length - take, take);
+  }
+
+  /** return puts tiles back into the bag and reshuffles, as when a player exchanges tiles. */
+  return(tiles: readonly number[]): void {
+    for (const t of tiles) this.tiles.push(t);
+    this.shuffle();
+  }
+
+  // shuffle randomises the remaining tiles in place with the bag's own PRNG (Fisher–Yates).
+  private shuffle(): void {
+    for (let i = this.tiles.length - 1; i > 0; i--) {
+      const j = Math.floor(this.rand() * (i + 1));
+      const tmp = this.tiles[i];
+      this.tiles[i] = this.tiles[j];
+      this.tiles[j] = tmp;
+    }
+  }
+}

ui/src/lib/localgame/board.ts

@@ -0,0 +1,44 @@
+// The mutable local-game board: a 15x15 row-major grid of placed tiles (alphabet-index letter
+// plus a blank flag). It satisfies the read view the validator and generator need (GenBoard,
+// which extends validate.ts's Board) and adds set() so the engine can apply a play. The board is
+// alphabet-agnostic — a cell's letter is a variant index, meaningful with the variant's ruleset.
+
+import { BOARD_SIZE } from '../premiums';
+import type { Cell } from '../dict/validate';
+import type { GenBoard } from '../dict/generate';
+
+/** LocalBoard is the engine's in-memory board; it reads as a GenBoard and applies plays via set. */
+export class LocalBoard implements GenBoard {
+  readonly rows = BOARD_SIZE;
+  readonly cols = BOARD_SIZE;
+  private readonly grid: (Cell | null)[];
+  private count = 0;
+
+  constructor() {
+    this.grid = new Array<Cell | null>(BOARD_SIZE * BOARD_SIZE).fill(null);
+  }
+
+  inBounds(row: number, col: number): boolean {
+    return row >= 0 && row < this.rows && col >= 0 && col < this.cols;
+  }
+
+  filled(row: number, col: number): boolean {
+    return this.inBounds(row, col) && this.grid[row * this.cols + col] !== null;
+  }
+
+  cellAt(row: number, col: number): Cell {
+    return this.grid[row * this.cols + col]!;
+  }
+
+  isEmpty(): boolean {
+    return this.count === 0;
+  }
+
+  /** set places a tile at (row, col). It assumes the square was empty (a play only lays tiles
+   *  on empty squares), keeping the filled count exact for isEmpty. */
+  set(row: number, col: number, letter: number, blank: boolean): void {
+    const i = row * this.cols + col;
+    if (this.grid[i] === null) this.count++;
+    this.grid[i] = { letter, blank };
+  }
+}

ui/src/lib/localgame/engine.parity.test.ts

@@ -0,0 +1,35 @@
+import { describe, it, expect } from 'vitest';
+import { readFileSync } from 'node:fs';
+import { applyEndAdjustment, winner, type EndReason } from './engine';
+import { RULESETS } from './ruleset';
+import type { Variant } from '../model';
+
+// The offline engine must settle unplayed racks and decide the winner exactly as the Go engine
+// does, so a local game finishes with the same scores. Golden from the in-package emitter
+// (backend/internal/engine/endfixture_test.go).
+interface EndCase {
+  name: string;
+  variant: Variant;
+  reason: EndReason;
+  hands: number[][];
+  scores: number[];
+  resigned: boolean[];
+  toMove: number;
+  scoresAfter: number[];
+  winner: number;
+}
+
+const fx = JSON.parse(
+  readFileSync(new URL('./testdata/endgame.json', import.meta.url), 'utf8'),
+) as { cases: EndCase[] };
+
+describe('offline engine end-game parity vs Go', () => {
+  for (const c of fx.cases) {
+    it(c.name, () => {
+      const values = RULESETS[c.variant].values;
+      const after = applyEndAdjustment(c.reason, c.hands, c.scores, c.toMove, values);
+      expect(after).toEqual(c.scoresAfter);
+      expect(winner(true, c.reason, after, c.resigned)).toBe(c.winner);
+    });
+  }
+});

ui/src/lib/localgame/engine.test.ts

@@ -0,0 +1,78 @@
+import { describe, it, expect } from 'vitest';
+import { readFileSync } from 'node:fs';
+import { Dawg } from '../dict/dawg';
+import { RACK_SIZE } from '../premiums';
+import { LocalGame } from './engine';
+import { decide } from '../robot/strategy';
+import type { Move } from '../dict/validate';
+
+// A full-loop smoke: two robots play a whole local vs_ai game to completion over the committed
+// sample dictionary, exercising deal / play / refill / exchange / pass / end detection / winner.
+// (The rich full-dictionary robot behaviour is pinned elsewhere by the generator + strategy parity
+// suites; this test proves the engine drives to a valid finish.)
+const dawg = new Dawg(new Uint8Array(readFileSync(new URL('../dict/testdata/sample_en.dawg', import.meta.url))));
+
+function bestOpponentScore(game: LocalGame, seat: number): number {
+  let best = 0;
+  for (let i = 0; i < game.playerCount; i++) if (i !== seat) best = Math.max(best, game.scoreOf(i));
+  return best;
+}
+
+// robotTurn plays the seat to move: it picks the robot's action from the ranked legal plays and
+// dispatches it. The sample dict has a one-letter word ("a") the generator emits but the validator
+// rejects (len < 2) — real dictionaries have none, so filtering to main length >= 2 is a no-op in
+// production; an exchange the bag is too small to satisfy falls back to a pass.
+function robotTurn(game: LocalGame, seed: bigint): void {
+  const seat = game.currentPlayer;
+  const cands: Move[] = game.generateMoves().filter((m) => m.main.letters.length >= 2);
+  const dec = decide(seed, game.moveCount, cands, game.scoreOf(seat), bestOpponentScore(game, seat), game.handOf(seat), game.bagLength);
+  if (dec.kind === 'play') {
+    game.play(dec.move.dir, dec.move.tiles);
+  } else if (dec.kind === 'exchange' && game.bagLength >= RACK_SIZE) {
+    game.exchange(dec.exchange);
+  } else {
+    game.pass();
+  }
+}
+
+describe('offline engine full-game smoke', () => {
+  it('plays a whole 2-player vs_ai game to completion', () => {
+    const game = new LocalGame({
+      variant: 'scrabble_en',
+      version: 'sample',
+      seed: 123456789n,
+      players: 2,
+      dawg,
+      multipleWords: true,
+    });
+
+    let turns = 0;
+    while (!game.isOver && turns < 2000) {
+      robotTurn(game, game.seed);
+      turns++;
+    }
+
+    expect(game.isOver).toBe(true);
+    expect(turns).toBeLessThan(2000);
+    expect(['out_of_tiles', 'scoreless', 'resign']).toContain(game.endReason);
+
+    const w = game.winnerIndex;
+    expect(w === -1 || (w >= 0 && w < game.playerCount)).toBe(true);
+    for (let i = 0; i < game.playerCount; i++) expect(Number.isInteger(game.scoreOf(i))).toBe(true);
+    // The move log recorded every turn.
+    expect(game.history.length).toBe(turns);
+  });
+
+  it('is reproducible from the seed', () => {
+    const play = (): { reason: string; scores: number[]; turns: number } => {
+      const g = new LocalGame({ variant: 'scrabble_en', version: 'sample', seed: 42n, players: 2, dawg, multipleWords: true });
+      let t = 0;
+      while (!g.isOver && t < 2000) {
+        robotTurn(g, g.seed);
+        t++;
+      }
+      return { reason: g.endReason, scores: [g.scoreOf(0), g.scoreOf(1)], turns: t };
+    };
+    expect(play()).toEqual(play());
+  });
+});