fix(deploy): route /dict through caddy to the gateway (local eval)

The edge caddy @gateway matcher was missing /dict/*, so the client's dictionary
fetch fell to the static landing catch-all: it received a non-dawg blob (200 OK),
which the reader parsed into a bogus finder that reports every word missing — a
valid first move showed as illegal with no network fallback. Add /dict/* to the
gateway route.

Hardening + the cross-test that would have caught it:
- reader: reject a blob whose 32-bit size header != its byte length, so a
  non-dawg page or a truncated download now throws and the loader falls back to
  the network preview instead of silently validating against garbage.
- eval.parity: an adapter conformance suite that drives evaluateLocal through the
  real letter-space path (the server alphabet table, a letter board and letter
  placements) against the engine — the algorithm-level validate.parity did not
  exercise the adapter. validategen now emits the alphabet table for it.
- a CI deploy probe asserts {edge}/dict reaches the gateway (401), not the landing.
- the DebugPanel reports the feature flag, the bad-connection breaker and the
  cached dictionaries with their sizes; its reset also clears the dict cache.

.gitea/workflows/ci.yaml

@@ -395,6 +395,23 @@ jobs:
           docker logs --tail 50 scrabble-backend || true
           exit 1
 
+      - name: Probe the /dict edge route reaches the gateway
+        run: |
+          set -u
+          # The client fetches each game's dictionary blob at {edge}/dict/{variant}/{version}
+          # for the local move preview. If caddy does not route /dict to the gateway the request
+          # falls to the static landing and the client silently gets a non-dawg blob. Probed
+          # unauthenticated it must be the gateway's 401 (the route reaches the gateway), never a
+          # 404/200 from the landing catch-all.
+          out="$(docker run --rm --network edge alpine:3.20 wget -S -q -O /dev/null http://scrabble/dict/scrabble_en/v1 2>&1 || true)"
+          echo "$out" | grep -E "HTTP/" || true
+          if echo "$out" | grep -q " 401"; then
+            echo "ok: /dict reaches the gateway (401 unauthenticated)"
+          else
+            echo "FAIL: /dict did not reach the gateway (expected 401) — caddy route missing?"
+            exit 1
+          fi
+
       - name: Probe the Telegram validator and bot liveness
         run: |
           set -u

backend/cmd/validategen/main.go

@@ -67,18 +67,28 @@ type fixture struct {
 	Cross            []word `json:"cross,omitempty"`
 }
 
+// alphaEntry mirrors one row of the per-variant alphabet table the server sends the
+// client (index, concrete letter as the ruleset emits it, tile value), so the adapter
+// cross-test can drive the letter-space client path exactly as production does.
+type alphaEntry struct {
+	Index  int    `json:"index"`
+	Letter string `json:"letter"`
+	Value  int    `json:"value"`
+}
+
 // variantFile is the whole conformance payload for one variant.
 type variantFile struct {
-	Variant  string    `json:"variant"`
+	Variant  string       `json:"variant"`
-	Rows     int       `json:"rows"`
+	Rows     int          `json:"rows"`
-	Cols     int       `json:"cols"`
+	Cols     int          `json:"cols"`
-	Center   int       `json:"center"`
+	Center   int          `json:"center"`
-	RackSize int       `json:"rackSize"`
+	RackSize int          `json:"rackSize"`
-	Bingo    int       `json:"bingo"`
+	Bingo    int          `json:"bingo"`
-	Values   []int     `json:"values"`
+	Values   []int        `json:"values"`
-	Premiums []int     `json:"premiums"` // row-major rules.Premium codes
+	Premiums []int        `json:"premiums"` // row-major rules.Premium codes
-	Boards   [][]cell  `json:"boards"`
+	Alphabet []alphaEntry `json:"alphabet"`
-	Fixtures []fixture `json:"fixtures"`
+	Boards   [][]cell     `json:"boards"`
+	Fixtures []fixture    `json:"fixtures"`
 }
 
 func main() {
@@ -123,7 +133,7 @@ func generate(sp variantSpec, dawgDir, outDir string, games, plies int) error {
 	out := variantFile{
 		Variant: sp.name, Rows: rs.Rows, Cols: rs.Cols, Center: rs.Center,
 		RackSize: rs.RackSize, Bingo: rs.Bingo, Values: rs.Values,
-		Premiums: premiumCodes(rs),
+		Premiums: premiumCodes(rs), Alphabet: alphabetOf(rs),
 	}
 
 	// Capture under both the standard rule and the single-word rule, building the
@@ -284,6 +294,16 @@ func toWord(w scrabble.Word) *word {
 	}
 }
 
+func alphabetOf(rs *rules.Ruleset) []alphaEntry {
+	n := rs.Alphabet.Size()
+	out := make([]alphaEntry, n)
+	for i := range n {
+		ch, _ := rs.Alphabet.Character(byte(i))
+		out[i] = alphaEntry{Index: i, Letter: ch, Value: rs.Values[i]}
+	}
+	return out
+}
+
 func premiumCodes(rs *rules.Ruleset) []int {
 	codes := make([]int, rs.Rows*rs.Cols)
 	for i := range codes {

deploy/caddy/Caddyfile

@@ -53,7 +53,7 @@
 	# The game SPA and the Connect edge are served by the gateway. Strip any
 	# client-supplied X-Scrabble-Honeypot here so the gateway only ever honours the
 	# tag the honeypot block sets below (a client cannot self-tag a real request).
-	@gateway path /app /app/* /telegram /telegram/* /vk /vk/* /scrabble.edge.v1.Gateway/*
+	@gateway path /app /app/* /telegram /telegram/* /vk /vk/* /dict/* /scrabble.edge.v1.Gateway/*
 	handle @gateway {
 		reverse_proxy gateway:8081 {
 			header_up -X-Scrabble-Honeypot

ui/src/components/DebugPanel.svelte

@@ -4,18 +4,39 @@
   // snapshot (no secrets, no initData values, no IP) and shares it through the OS share sheet (or a
   // clipboard copy on desktop) — a support aid for reproducing client-specific issues, e.g. the
   // Telegram Android presentation quirks. Drawn from the top, just under the app header.
+  import { onMount } from 'svelte';
   import { app, closeDebug, resetOnboarding } from '../lib/app.svelte';
   import { connection } from '../lib/connection.svelte';
   import { shareText } from '../lib/share';
   import { telegramChromeDiag } from '../lib/telegram';
 
-  const report = [
+  // The local move-preview snapshot — the feature flag, the bad-connection breaker and the
-    `app: ${__APP_VERSION__}`,
+  // dictionaries cached in IndexedDB with their sizes — loads async so a report about the
-    `locale: ${app.locale}  theme: ${app.theme}  reduceMotion: ${app.reduceMotion}`,
+  // preview is precise. Dynamically imported so the debug panel keeps the dict code lazy.
-    `online: ${connection.online}  streamAlive: ${app.streamAlive}`,
+  let dictInfo = $state('local eval: …');
-    `userId: ${app.session?.userId ?? '—'}  guest: ${app.profile?.isGuest ?? '—'}`,
+  onMount(() => {
-    telegramChromeDiag(),
+    void (async () => {
-  ].join('\n');
+      try {
+        const m = await import('../lib/dict');
+        const list = await m.listCachedDicts();
+        const cached = list.length ? list.map((d) => `${d.key}=${(d.bytes / 1024).toFixed(0)}KB`).join(' ') : 'none';
+        dictInfo = `local eval: ${m.LOCAL_EVAL_ENABLED ? 'on' : 'off'}  breaker: ${m.dictLoadingDisabled() ? 'TRIPPED' : 'ok'}\ndicts cached: ${cached}`;
+      } catch {
+        dictInfo = 'local eval: n/a';
+      }
+    })();
+  });
+
+  const report = $derived(
+    [
+      `app: ${__APP_VERSION__}`,
+      `locale: ${app.locale}  theme: ${app.theme}  reduceMotion: ${app.reduceMotion}`,
+      `online: ${connection.online}  streamAlive: ${app.streamAlive}`,
+      `userId: ${app.session?.userId ?? '—'}  guest: ${app.profile?.isGuest ?? '—'}`,
+      telegramChromeDiag(),
+      dictInfo,
+    ].join('\n'),
+  );
 
   let label = $state('Share');
   async function share(e: MouseEvent): Promise<void> {
@@ -35,8 +56,10 @@
     resetOnboarding();
     // Also clear the local move-preview dictionary cache (safe — it re-downloads).
     // Dynamically imported so the debug panel keeps the dict code out of the app bundle.
-    void import('../lib/dict/store').then((m) => m.clearDictCache());
+    void import('../lib/dict').then((m) => {
-    void import('../lib/dict/loader').then((m) => m.clearDictInstances());
+      m.clearDictCache();
+      m.clearDictInstances();
+    });
     resetLabel = 'Cleared — relaunch';
     setTimeout(() => (resetLabel = 'Reset visited'), 1800);
   }

ui/src/lib/dict/dawg.ts

@@ -43,6 +43,16 @@ export class Dawg {
   constructor(bytes: Uint8Array) {
     this.bytes = bytes;
 
+    // Reject anything that is not a serialized dawg — e.g. an HTML error page or a
+    // truncated download routed here by mistake. The 32-bit big-endian header size is
+    // the total byte length; if it does not match, the blob is not a dawg. Without
+    // this guard a non-dawg blob would parse into a bogus reader that silently reports
+    // every word as missing (so the caller must throw here to fall back to the network).
+    const declaredSize = ((bytes[0] << 24) | (bytes[1] << 16) | (bytes[2] << 8) | bytes[3]) >>> 0;
+    if (declaredSize !== bytes.length) {
+      throw new Error(`dawg: not a dawg blob (size header ${declaredSize} != ${bytes.length} bytes)`);
+    }
+
     // Header: 32-bit size (skipped — the whole file is already in memory), then
     // cbits, abits, the language code string, and the word/node/edge counts.
     this.p = 32;

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

@@ -0,0 +1,110 @@
+import { describe, it, expect } from 'vitest';
+import { readFileSync, existsSync } from 'node:fs';
+import { join } from 'node:path';
+import { Dawg } from './dawg';
+import { evaluateLocal } from './eval';
+import { setAlphabet } from '../alphabet';
+import type { Board as ClientBoard, BoardCell } from '../board';
+import type { PlacedTile } from '../client';
+import type { Variant } from '../model';
+
+// End-to-end conformance for the local-eval ADAPTER: it drives evaluateLocal through
+// the real letter-space client path (the server-sent alphabet table, a letter board,
+// letter placements) and asserts it matches the Go engine's EvalResult for every
+// fixture. This is the cross-test the algorithm-level validate.parity suite does not
+// cover — it exercises the letter<->index mapping, the ruleset assembly and the word
+// decode, not just the index-space validator. Env-gated like the other parity suites.
+const dawgDir = process.env.DICT_DAWG_DIR;
+const validDir = process.env.DICT_VALID_DIR;
+const ready = !!dawgDir && !!validDir && existsSync(dawgDir) && existsSync(validDir);
+
+const dawgFile: Record<string, string> = {
+  scrabble_en: 'en_sowpods.dawg',
+  scrabble_ru: 'ru_scrabble.dawg',
+  erudit_ru: 'ru_erudit.dawg',
+};
+
+interface FxCell {
+  R: number;
+  C: number;
+  Letter: number;
+  Blank: boolean;
+}
+interface FxWord {
+  Letters: number[];
+}
+interface Fx {
+  board: number;
+  ignoreCrossWords: boolean;
+  tiles: FxCell[];
+  legal: boolean;
+  score: number;
+  main?: FxWord;
+  cross?: FxWord[];
+}
+interface Alpha {
+  index: number;
+  letter: string;
+  value: number;
+}
+interface VF {
+  rows: number;
+  cols: number;
+  alphabet: Alpha[];
+  boards: (FxCell[] | null)[];
+  fixtures: Fx[];
+}
+
+describe.skipIf(!ready)('local-eval adapter parity vs Go engine', () => {
+  for (const variant of Object.keys(dawgFile)) {
+    it(
+      variant,
+      () => {
+        const vf: VF = JSON.parse(readFileSync(join(validDir!, `${variant}.fixtures.json`), 'utf8'));
+        const dawg = new Dawg(new Uint8Array(readFileSync(join(dawgDir!, dawgFile[variant]))));
+        const v = variant as Variant;
+
+        // Seed the alphabet cache exactly as the server would (wire entries, lower-cased
+        // letters); the adapter re-encodes through it, just like production.
+        setAlphabet(v, vf.alphabet.map((a) => ({ index: a.index, letter: a.letter, value: a.value })));
+        const upper = vf.alphabet.map((a) => a.letter.toUpperCase());
+        const lower = vf.alphabet.map((a) => a.letter);
+
+        let legalCount = 0;
+        let mismatches = 0;
+        const first: string[] = [];
+
+        for (let fi = 0; fi < vf.fixtures.length; fi++) {
+          const fx = vf.fixtures[fi];
+
+          // Build the client's letter-space board and placements from the fixture.
+          const board: ClientBoard = Array.from({ length: vf.rows }, () =>
+            Array.from({ length: vf.cols }, () => null as BoardCell | null),
+          );
+          for (const cl of vf.boards[fx.board] ?? []) board[cl.R][cl.C] = { letter: upper[cl.Letter], blank: cl.Blank };
+          const tiles: PlacedTile[] = fx.tiles.map((t) => ({ row: t.R, col: t.C, letter: upper[t.Letter], blank: t.Blank }));
+
+          const res = evaluateLocal(dawg, v, board, tiles, !fx.ignoreCrossWords);
+
+          if (fx.legal) legalCount++;
+
+          let ok = res.legal === fx.legal;
+          if (ok && fx.legal) {
+            const wantWords = [fx.main!, ...(fx.cross ?? [])].map((w) => w.Letters.map((i) => lower[i]).join(''));
+            ok = res.score === fx.score && res.words.length === wantWords.length && res.words.every((w, i) => w === wantWords[i]);
+          }
+          if (!ok) {
+            mismatches++;
+            if (first.length < 8) {
+              first.push(`#${fi} exp legal=${fx.legal} score=${fx.score} got legal=${res.legal} score=${res.score} words=${JSON.stringify(res.words)}`);
+            }
+          }
+        }
+
+        expect(legalCount, 'fixtures should include legal plays').toBeGreaterThan(0);
+        expect(mismatches, first.join(' | ')).toBe(0);
+      },
+      120_000,
+    );
+  }
+});

ui/src/lib/dict/index.ts

@@ -3,5 +3,6 @@
 // of the initial app bundle — it is a progressive enhancement over the network
 // preview, which remains the fallback.
 export { evaluateLocal } from './eval';
-export { getDawg, peekDawg, hasDawg, dictLoadingDisabled } from './loader';
+export { getDawg, peekDawg, hasDawg, dictLoadingDisabled, clearDictInstances } from './loader';
+export { clearDictCache, listCachedDicts } from './store';
 export { LOCAL_EVAL_ENABLED } from './config';

ui/src/lib/dict/store.ts

@@ -84,6 +84,36 @@ export async function requestPersist(): Promise<void> {
   }
 }
 
+/**
+ * listCachedDicts returns the key (variant@version) and byte length of every cached
+ * dictionary blob, for the debug panel's local-dictionary readout. Best-effort: an
+ * empty list on any failure.
+ */
+export async function listCachedDicts(): Promise<Array<{ key: string; bytes: number }>> {
+  const db = openDb();
+  if (!db) return [];
+  try {
+    const d = await db;
+    return await new Promise((resolve) => {
+      const out: Array<{ key: string; bytes: number }> = [];
+      const req = d.transaction(STORE, 'readonly').objectStore(STORE).openCursor();
+      req.onsuccess = () => {
+        const cur = req.result;
+        if (!cur) {
+          resolve(out);
+          return;
+        }
+        const v = cur.value as ArrayBuffer;
+        out.push({ key: String(cur.key), bytes: v?.byteLength ?? 0 });
+        cur.continue();
+      };
+      req.onerror = () => resolve(out);
+    });
+  } catch {
+    return [];
+  }
+}
+
 /**
  * clearDictCache empties the dictionary blob store (backs the DebugPanel reset). The
  * store is cleared rather than the database deleted, to avoid a delete blocked on an