R6(a): de-stage code, docs, READMEs; split stage6_test

Mechanical, behaviour-preserving removal of Stage N / TODO-N / phase (RN)
references from comments, doc-comments, service READMEs, the current-state docs
(ARCHITECTURE, FUNCTIONAL+_ru, TESTING, UI_DESIGN), config-file comments, and the
.fbs/.proto schema comments. PLAN.md / PRERELEASE.md / CLAUDE.md keep the stage
history.

- Rename the only stage-named identifiers: registerStage8 -> registerSocialOps,
  registerStage11 -> registerLinkOps (gateway transcode).
- Split stage6_test.go: TestEmailLoginFlow -> email_test.go,
  TestGuestAutoMatchLeavesNoStats (+ provisionGuest) -> account_test.go.
- Regenerated proto bindings (push.pb.go, telegram_grpc.pb.go) from the de-staged
  .proto comments; FB Go/TS bindings unchanged (flatc strips schema comments).

go build/vet/gofmt clean across modules; integration typecheck and pnpm check green.

backend/internal/inttest/account_test.go

@@ -11,6 +11,8 @@ import (
 	"github.com/google/uuid"
 
 	"scrabble/backend/internal/account"
+	"scrabble/backend/internal/engine"
+	"scrabble/backend/internal/game"
 )
 
 // TestAccountProvisionByIdentity covers find-or-create semantics, distinct
@@ -78,7 +80,7 @@ func TestAccountProvisionByIdentity(t *testing.T) {
 }
 
 // TestGetStatsZeroForFreshAccount checks that an account with no finished games
-// reads back the zero statistics rather than an error (the Stage 8 stats screen).
+// reads back the zero statistics rather than an error (the stats screen).
 func TestGetStatsZeroForFreshAccount(t *testing.T) {
 	ctx := context.Background()
 	store := account.NewStore(testDB)
@@ -109,7 +111,7 @@ func identityConfirmed(t *testing.T, kind, externalID string) bool {
 // TestProvisionTelegramSeedsNewAccountOnly checks that Telegram first contact
 // seeds the new account's language and display name from the launch fields,
 // defaults the in-app-only flag on, and never overwrites an existing account on a
-// later login (Stage 9 language seeding).
+// later login (language seeding).
 func TestProvisionTelegramSeedsNewAccountOnly(t *testing.T) {
 	ctx := context.Background()
 	store := account.NewStore(testDB)
@@ -196,7 +198,7 @@ func TestServiceLanguageRoundTrip(t *testing.T) {
 	}
 }
 
-// TestHighRateFlagRoundTrip covers the R3 soft high-rate marker: a fresh account
+// TestHighRateFlagRoundTrip covers the soft high-rate marker: a fresh account
 // is unflagged, FlagHighRate stamps it exactly once (a second sustained episode
 // never moves the timestamp), ClearHighRateFlag reverses it, and a re-flag after
 // the operator clear takes a fresh timestamp.
@@ -279,7 +281,7 @@ func TestIdentityExternalID(t *testing.T) {
 	}
 }
 
-// TestNotificationsInAppOnlyRoundTrip checks the Stage 9 profile flag persists
+// TestNotificationsInAppOnlyRoundTrip checks the profile flag persists
 // through UpdateProfile and reads back through GetByID.
 func TestNotificationsInAppOnlyRoundTrip(t *testing.T) {
 	ctx := context.Background()
@@ -311,3 +313,72 @@ func TestNotificationsInAppOnlyRoundTrip(t *testing.T) {
 		t.Error("GetByID still reports in-app-only after clearing")
 	}
 }
+
+// provisionGuest creates a fresh ephemeral guest account and returns its id.
+func provisionGuest(t *testing.T) uuid.UUID {
+	t.Helper()
+	acc, err := account.NewStore(testDB).ProvisionGuest(context.Background())
+	if err != nil {
+		t.Fatalf("provision guest: %v", err)
+	}
+	if !acc.IsGuest {
+		t.Fatalf("provisioned account %s is not flagged guest", acc.ID)
+	}
+	return acc.ID
+}
+
+// TestGuestAutoMatchLeavesNoStats drives a guest through a full auto-match game
+// against a robot to a natural end and checks the guest holds a seat (the
+// game_players foreign key is satisfied) yet accrues no statistics, while the
+// durable robot opponent does.
+func TestGuestAutoMatchLeavesNoStats(t *testing.T) {
+	ctx := context.Background()
+	svc := newGameService()
+	robots := newRobotService(t, svc)
+	if err := robots.EnsurePool(ctx); err != nil {
+		t.Fatalf("ensure pool: %v", err)
+	}
+	robotID, err := robots.Pick(engine.VariantEnglish)
+	if err != nil {
+		t.Fatalf("pick: %v", err)
+	}
+	guest := provisionGuest(t)
+	seed := openingSeed(t)
+
+	g, err := svc.Create(ctx, game.CreateParams{
+		Variant: engine.VariantEnglish, Seats: []uuid.UUID{guest, robotID},
+		TurnTimeout: 24 * time.Hour, Seed: seed,
+	})
+	if err != nil {
+		t.Fatalf("create: %v", err)
+	}
+	const robotSeat = 1 // seats = [guest, robot]
+
+	finished := false
+	for i := 0; i < 400 && !finished; i++ {
+		_, toMove, status, err := svc.Participants(ctx, g.ID)
+		if err != nil {
+			t.Fatalf("participants: %v", err)
+		}
+		if status != game.StatusActive {
+			finished = true
+			break
+		}
+		if toMove == robotSeat {
+			setTurnStarted(t, g.ID, daytime.Add(-2*time.Hour))
+			robots.Drive(ctx, daytime)
+			continue
+		}
+		playHuman(t, ctx, svc, g.ID, guest)
+	}
+	if !finished {
+		t.Fatal("guest game did not finish within the move budget")
+	}
+
+	if _, _, _, _, _, ok := readStats(t, guest); ok {
+		t.Error("a guest must not accrue a statistics row")
+	}
+	if _, _, _, _, _, ok := readStats(t, robotID); !ok {
+		t.Error("the durable robot opponent should have a statistics row")
+	}
+}

backend/internal/inttest/admin_test.go

@@ -169,7 +169,7 @@ func TestConsoleServesAndGuardsCSRF(t *testing.T) {
 }
 
 // TestConsoleGameDetailRobotSchedule checks the admin game card surfaces a robot seat's
-// play-to-win intent and, while it is the robot's turn, its next-move ETA (Stage 17).
+// play-to-win intent and, while it is the robot's turn, its next-move ETA.
 func TestConsoleGameDetailRobotSchedule(t *testing.T) {
 	ctx := context.Background()
 	svc := newGameService()
@@ -207,7 +207,7 @@ func TestConsoleGameDetailRobotSchedule(t *testing.T) {
 	}
 }
 
-// TestConsoleThrottledViewAndFlagClear drives the R3 rate-limit surface end to
+// TestConsoleThrottledViewAndFlagClear drives the rate-limit surface end to
 // end against real stores: a gateway report past the threshold auto-flags the
 // account, the throttled view shows the episode and the flagged account, the
 // user card carries the marker, and the operator clear (a same-origin POST)

backend/internal/inttest/draft_test.go

@@ -34,7 +34,7 @@ func newDraftGame(t *testing.T) (*game.Service, uuid.UUID, []uuid.UUID, engine.M
 	return svc, g.ID, seats, hint
 }
 
-// TestDraftPersistAndConflictReset covers Stage 17 draft persistence: a round-trip of the
+// TestDraftPersistAndConflictReset covers draft persistence: a round-trip of the
 // rack order + board tiles, the actor's own draft cleared on their move, and an opponent's
 // board draft reset when a committed play overlaps one of its cells (the rack order kept).
 func TestDraftPersistAndConflictReset(t *testing.T) {

backend/internal/inttest/email_test.go

@@ -159,7 +159,7 @@ func TestUpdateProfilePersists(t *testing.T) {
 	}
 }
 
-// TestUpdateProfileOffsetTimezone checks the Stage 8 UTC-offset timezone: it is
+// TestUpdateProfileOffsetTimezone checks the UTC-offset timezone: it is
 // accepted, persisted verbatim, and resolved to the right fixed offset.
 func TestUpdateProfileOffsetTimezone(t *testing.T) {
 	ctx := context.Background()
@@ -181,3 +181,49 @@ func TestUpdateProfileOffsetTimezone(t *testing.T) {
 		t.Fatalf("ResolveZone offset = %d, want 10800", off)
 	}
 }
+
+// TestEmailLoginFlow covers the email-as-login path: a code is mailed to
+// a new address, verifying it provisions and returns the owning account, and a
+// second login for the same address resolves to that same account (a returning
+// user), with the identity confirmed.
+func TestEmailLoginFlow(t *testing.T) {
+	ctx := context.Background()
+	mailer := &capturingMailer{}
+	svc := account.NewEmailService(account.NewStore(testDB), mailer)
+	email := "login-" + uuid.NewString() + "@example.com"
+
+	accountID, err := svc.RequestLoginCode(ctx, email)
+	if err != nil {
+		t.Fatalf("request login code: %v", err)
+	}
+	code := sixDigit.FindString(mailer.lastBody)
+	if code == "" {
+		t.Fatalf("no code in mail body %q", mailer.lastBody)
+	}
+
+	acc, err := svc.LoginWithCode(ctx, email, code)
+	if err != nil {
+		t.Fatalf("login with code: %v", err)
+	}
+	if acc.ID != accountID {
+		t.Errorf("login account = %s, want %s", acc.ID, accountID)
+	}
+	if acc.IsGuest {
+		t.Error("an email account must be durable, not a guest")
+	}
+	if !identityConfirmed(t, account.KindEmail, email) {
+		t.Error("the email identity must be confirmed after login")
+	}
+
+	// A second login for the same email is the returning user: same account.
+	if _, err := svc.RequestLoginCode(ctx, email); err != nil {
+		t.Fatalf("second request: %v", err)
+	}
+	acc2, err := svc.LoginWithCode(ctx, email, sixDigit.FindString(mailer.lastBody))
+	if err != nil {
+		t.Fatalf("second login: %v", err)
+	}
+	if acc2.ID != accountID {
+		t.Errorf("returning login account = %s, want %s", acc2.ID, accountID)
+	}
+}

backend/internal/inttest/game_test.go

@@ -299,7 +299,7 @@ func TestResignWinnerAndStats(t *testing.T) {
 	}
 }
 
-// TestResignOnOpponentTurn checks the Stage 17 fix: a player can forfeit on the
+// TestResignOnOpponentTurn checks a player can forfeit on the
 // opponent's turn. Seat 0 plays (so it is seat 1's turn), then seat 0 resigns its own
 // seat while it is not its turn — no ErrNotYourTurn, the game ends, and seat 0 loses
 // despite leading on score.
@@ -464,7 +464,7 @@ func TestHintPolicy(t *testing.T) {
 	}
 }
 
-// TestGameVariant covers the edge's lightweight variant lookup (Stage 13): it returns the
+// TestGameVariant covers the edge's lightweight variant lookup: it returns the
 // created game's variant and ErrNotFound for an unknown id.
 func TestGameVariant(t *testing.T) {
 	ctx := context.Background()
@@ -619,7 +619,7 @@ func equalStrings(a, b []string) bool {
 	return true
 }
 
-// TestExportGCGRefusesActiveGame checks the Stage 8 finished-only gate: a GCG export
+// TestExportGCGRefusesActiveGame checks the finished-only gate: a GCG export
 // is allowed only once the game is over, so an active game leaks nothing mid-play.
 func TestExportGCGRefusesActiveGame(t *testing.T) {
 	ctx := context.Background()

backend/internal/inttest/hide_test.go

@@ -12,7 +12,7 @@ import (
 	"scrabble/backend/internal/game"
 )
 
-// TestHideFinishedGame covers Stage 17 per-account game hiding: an active game cannot be
+// TestHideFinishedGame covers per-account game hiding: an active game cannot be
 // hidden, a finished game is removed from the hider's own list while staying visible to the
 // other player, an outsider cannot hide it, and the action is idempotent.
 func TestHideFinishedGame(t *testing.T) {

backend/internal/inttest/robot_test.go

@@ -97,7 +97,7 @@ func TestRobotPoolProvisionsRobotAccounts(t *testing.T) {
 		t.Fatalf("get robot account: %v", err)
 	}
 	// A robot blocks chat but NOT friend requests: a request to a robot stays pending and
-	// expires, mirroring a human who ignores it (Stage 17).
+	// expires, mirroring a human who ignores it.
 	if acc.DisplayName == "" || !acc.BlockChat || acc.BlockFriendRequests {
 		t.Errorf("robot profile wrong: name=%q chat-blocked=%v friends-blocked=%v (want chat blocked, friends open)",
 			acc.DisplayName, acc.BlockChat, acc.BlockFriendRequests)

backend/internal/inttest/social_test.go

@@ -70,7 +70,7 @@ func newGameWithSeats(t *testing.T, n int) (uuid.UUID, []uuid.UUID) {
 
 // TestFriendRequestToRobotStaysPending checks a friend request to a robot is accepted as
 // pending rather than blocked: robots no longer block friend requests, so the request
-// just sits unanswered and later expires — mirroring a human who ignores it (Stage 17).
+// just sits unanswered and later expires — mirroring a human who ignores it.
 func TestFriendRequestToRobotStaysPending(t *testing.T) {
 	ctx := context.Background()
 	svc := newSocialService()
@@ -342,7 +342,7 @@ func TestChatRejectsBadContent(t *testing.T) {
 	}
 }
 
-// TestChatOnlyOnYourTurn checks chat is allowed only on the sender's own turn (Stage 17):
+// TestChatOnlyOnYourTurn checks chat is allowed only on the sender's own turn:
 // the player to move can post, the waiting player gets ErrChatNotYourTurn.
 func TestChatOnlyOnYourTurn(t *testing.T) {
 	ctx := context.Background()
@@ -383,7 +383,7 @@ func TestNudgeRulesAndRateLimit(t *testing.T) {
 }
 
 // TestNudgeCooldownResetsOnAction checks the nudge cooldown clears once the player has
-// acted (moved or chatted) since their last nudge, even within the hour (Stage 17).
+// acted (moved or chatted) since their last nudge, even within the hour.
 func TestNudgeCooldownResetsOnAction(t *testing.T) {
 	ctx := context.Background()
 	svc := newSocialService()
@@ -413,7 +413,7 @@ func TestNudgeCooldownResetsOnAction(t *testing.T) {
 }
 
 // TestListOutgoingRequests checks the requester-side list that backs the in-game "add to
-// friends" item (Stage 17): a pending request shows for the requester only; an accepted one
+// friends" item: a pending request shows for the requester only; an accepted one
 // clears (it is a friendship now); a declined one stays (cannot be re-sent, so it reads as
 // still "sent"); a lazily expired pending one drops (it may be re-sent).
 func TestListOutgoingRequests(t *testing.T) {
@@ -469,7 +469,7 @@ func TestListOutgoingRequests(t *testing.T) {
 }
 
 // TestRespondPublishesToRequester checks that answering a request notifies the original
-// requester over the live channel (Stage 17): accept -> friend_added, decline ->
+// requester over the live channel: accept -> friend_added, decline ->
 // friend_declined, so a game screen watching that opponent re-derives its friend state.
 func TestRespondPublishesToRequester(t *testing.T) {
 	ctx := context.Background()
@@ -503,7 +503,7 @@ func TestRespondPublishesToRequester(t *testing.T) {
 }
 
 // TestNudgeRoutedByGameLanguage checks a nudge's out-of-app push carries the game's language, so
-// it is delivered by the game's bot rather than the recipient's last-login bot (Stage 17).
+// it is delivered by the game's bot rather than the recipient's last-login bot.
 func TestNudgeRoutedByGameLanguage(t *testing.T) {
 	ctx := context.Background()
 	svc := newSocialService()
@@ -528,7 +528,7 @@ func TestNudgeRoutedByGameLanguage(t *testing.T) {
 	}
 }
 
-// TestAdminListMessages checks the admin moderation list (Stage 17): real messages only
+// TestAdminListMessages checks the admin moderation list: real messages only
 // (nudges excluded), the game / sender pins, the sender glob masks, and the source label.
 func TestAdminListMessages(t *testing.T) {
 	ctx := context.Background()

backend/internal/inttest/stage6_test.go

@@ -1,130 +0,0 @@
-//go:build integration
-
-package inttest
-
-import (
-	"context"
-	"testing"
-	"time"
-
-	"github.com/google/uuid"
-
-	"scrabble/backend/internal/account"
-	"scrabble/backend/internal/engine"
-	"scrabble/backend/internal/game"
-)
-
-// provisionGuest creates a fresh ephemeral guest account and returns its id.
-func provisionGuest(t *testing.T) uuid.UUID {
-	t.Helper()
-	acc, err := account.NewStore(testDB).ProvisionGuest(context.Background())
-	if err != nil {
-		t.Fatalf("provision guest: %v", err)
-	}
-	if !acc.IsGuest {
-		t.Fatalf("provisioned account %s is not flagged guest", acc.ID)
-	}
-	return acc.ID
-}
-
-// TestGuestAutoMatchLeavesNoStats drives a guest through a full auto-match game
-// against a robot to a natural end and checks the guest holds a seat (the
-// game_players foreign key is satisfied) yet accrues no statistics, while the
-// durable robot opponent does.
-func TestGuestAutoMatchLeavesNoStats(t *testing.T) {
-	ctx := context.Background()
-	svc := newGameService()
-	robots := newRobotService(t, svc)
-	if err := robots.EnsurePool(ctx); err != nil {
-		t.Fatalf("ensure pool: %v", err)
-	}
-	robotID, err := robots.Pick(engine.VariantEnglish)
-	if err != nil {
-		t.Fatalf("pick: %v", err)
-	}
-	guest := provisionGuest(t)
-	seed := openingSeed(t)
-
-	g, err := svc.Create(ctx, game.CreateParams{
-		Variant: engine.VariantEnglish, Seats: []uuid.UUID{guest, robotID},
-		TurnTimeout: 24 * time.Hour, Seed: seed,
-	})
-	if err != nil {
-		t.Fatalf("create: %v", err)
-	}
-	const robotSeat = 1 // seats = [guest, robot]
-
-	finished := false
-	for i := 0; i < 400 && !finished; i++ {
-		_, toMove, status, err := svc.Participants(ctx, g.ID)
-		if err != nil {
-			t.Fatalf("participants: %v", err)
-		}
-		if status != game.StatusActive {
-			finished = true
-			break
-		}
-		if toMove == robotSeat {
-			setTurnStarted(t, g.ID, daytime.Add(-2*time.Hour))
-			robots.Drive(ctx, daytime)
-			continue
-		}
-		playHuman(t, ctx, svc, g.ID, guest)
-	}
-	if !finished {
-		t.Fatal("guest game did not finish within the move budget")
-	}
-
-	if _, _, _, _, _, ok := readStats(t, guest); ok {
-		t.Error("a guest must not accrue a statistics row")
-	}
-	if _, _, _, _, _, ok := readStats(t, robotID); !ok {
-		t.Error("the durable robot opponent should have a statistics row")
-	}
-}
-
-// TestEmailLoginFlow covers the Stage 6 email-as-login path: a code is mailed to
-// a new address, verifying it provisions and returns the owning account, and a
-// second login for the same address resolves to that same account (a returning
-// user), with the identity confirmed.
-func TestEmailLoginFlow(t *testing.T) {
-	ctx := context.Background()
-	mailer := &capturingMailer{}
-	svc := account.NewEmailService(account.NewStore(testDB), mailer)
-	email := "login-" + uuid.NewString() + "@example.com"
-
-	accountID, err := svc.RequestLoginCode(ctx, email)
-	if err != nil {
-		t.Fatalf("request login code: %v", err)
-	}
-	code := sixDigit.FindString(mailer.lastBody)
-	if code == "" {
-		t.Fatalf("no code in mail body %q", mailer.lastBody)
-	}
-
-	acc, err := svc.LoginWithCode(ctx, email, code)
-	if err != nil {
-		t.Fatalf("login with code: %v", err)
-	}
-	if acc.ID != accountID {
-		t.Errorf("login account = %s, want %s", acc.ID, accountID)
-	}
-	if acc.IsGuest {
-		t.Error("an email account must be durable, not a guest")
-	}
-	if !identityConfirmed(t, account.KindEmail, email) {
-		t.Error("the email identity must be confirmed after login")
-	}
-
-	// A second login for the same email is the returning user: same account.
-	if _, err := svc.RequestLoginCode(ctx, email); err != nil {
-		t.Fatalf("second request: %v", err)
-	}
-	acc2, err := svc.LoginWithCode(ctx, email, sixDigit.FindString(mailer.lastBody))
-	if err != nil {
-		t.Fatalf("second login: %v", err)
-	}
-	if acc2.ID != accountID {
-		t.Errorf("returning login account = %s, want %s", acc2.ID, accountID)
-	}
-}