feat(lobby): enter the game immediately and wait for the opponent inside it

Quick auto-match no longer waits on a separate screen: Enqueue opens a real game seating the caller with an empty opponent seat (new game status 'open') and the player enters it at once. A second human searching the same variant+rule joins that open game; otherwise a background reaper seats a robot after a 90s + random 0-90s wait, pushing a new in-app opponent_joined event that fills the opponent card and re-enables resign and chat in place.

Matchmaking state is now the open games in the database (the in-memory pool, lobby.poll and lobby.cancel are gone), serialised by a per-bucket advisory lock. While a game is open the starter may move on their turn, but resign, chat and nudge are refused; the lobby and opponent card show "searching for opponent".

Schema edited in the baseline (no prod data): 'open' status, nullable game_players.account_id for the empty seat, and a games.open_deadline_at stamp; jet code regenerated.

ui/src/lib/codec.test.ts

@@ -4,6 +4,7 @@ import * as fb from '../gen/fbs/scrabblefb';
 import { BLANK_INDEX, setAlphabet } from './alphabet';
 import {
   decodeDraftView,
+  decodeEvent,
   decodeFriendList,
   decodeGameList,
   decodeInvitation,
@@ -264,6 +265,19 @@ describe('codec', () => {
     expect(inv.invitees[0]).toEqual({ accountId: 'inv-1', displayName: 'Friend', seat: 1, response: 'pending' });
     expect(inv.variant).toBe('scrabble_en');
   });
+
+  it('decodes an opponent_joined event (reusing the match_found payload layout)', () => {
+    const b = new Builder(64);
+    const gid = b.createString('g-open');
+    fb.MatchFoundEvent.startMatchFoundEvent(b);
+    fb.MatchFoundEvent.addGameId(b, gid);
+    b.finish(fb.MatchFoundEvent.endMatchFoundEvent(b));
+    expect(decodeEvent('opponent_joined', b.asUint8Array())).toEqual({
+      kind: 'opponent_joined',
+      gameId: 'g-open',
+      state: undefined,
+    });
+  });
 });
 
 // The live play loop exchanges alphabet indices, mapped through the per-variant

ui/src/lib/codec.ts

@@ -465,6 +465,12 @@ export function decodeEvent(kind: string, payload: Uint8Array): PushEvent | null
       const st = e.state();
       return { kind: 'match_found', gameId: s(e.gameId()), state: st ? decodeStateViewTable(st) : undefined };
     }
+    case 'opponent_joined': {
+      // opponent_joined reuses the match_found payload layout (game id + the recipient's state).
+      const e = fb.MatchFoundEvent.getRootAsMatchFoundEvent(bb);
+      const st = e.state();
+      return { kind: 'opponent_joined', gameId: s(e.gameId()), state: st ? decodeStateViewTable(st) : undefined };
+    }
     case 'notify': {
       const e = fb.NotificationEvent.getRootAsNotificationEvent(bb);
       const acc = e.account();

ui/src/lib/gateway.ts

@@ -20,4 +20,9 @@ if (isMock && typeof window !== 'undefined') {
     offline: reportOffline,
     online: reportOnline,
   };
+  // Drive the auto-match opponent join deterministically from the e2e (the mock otherwise
+  // attaches a robot on a timer).
+  (window as unknown as { __mock?: { joinOpponent(): void } }).__mock = {
+    joinOpponent: () => (gateway as MockGateway).joinPendingOpponent(),
+  };
 }

ui/src/lib/i18n/en.ts

@@ -51,11 +51,14 @@ export const en = {
   'new.rulesRussian': '104 tiles · ё is a letter · bingo +50',
   'new.rulesErudit': '131 tiles · ё = е · no centre ×2 · bonus +15',
   'new.moveLimit': 'Move time: {n} h 00 min',
+  'new.searchHint':
+    'Finding an opponent can sometimes take a while. If you do not want to wait, close the app after starting the game and come back in a couple of minutes.',
 
   'game.bag': '{n} in the bag',
   'game.bagEmpty': 'Bag is empty',
   'game.hints': 'Hints {n}',
   'game.yourTurn': 'Your turn',
+  'game.searchingForOpponent': 'Searching for opponent…',
   'game.waiting': "Waiting for {name}",
   'game.makeMove': 'Make move',
   'game.reset': 'Reset',

ui/src/lib/i18n/ru.ts

@@ -52,11 +52,14 @@ export const ru: Record<MessageKey, string> = {
   'new.rulesRussian': '104 фишки · ё — отдельная буква · бинго +50',
   'new.rulesErudit': '131 фишка · ё = е · центр не удваивает · бонус +15',
   'new.moveLimit': 'Время на ход: {n} ч. 00 мин.',
+  'new.searchHint':
+    'Иногда поиск соперника может занимать некоторое время. Если не хотите ждать, после начала игры закройте приложение и возвращайтесь через пару минут.',
 
   'game.bag': '{n} в мешке',
   'game.bagEmpty': 'Мешок пуст',
   'game.hints': 'Подсказки {n}',
   'game.yourTurn': 'Ваш ход',
+  'game.searchingForOpponent': 'Поиск соперника...',
   'game.waiting': 'Ожидаем {name}',
   'game.makeMove': 'Сделать ход',
   'game.reset': 'Сброс',

ui/src/lib/mock/client.ts

@@ -88,6 +88,8 @@ export class MockGateway implements GatewayClient {
   private readonly profile: Profile = { ...PROFILE };
   private readonly subs = new Set<(e: PushEvent) => void>();
   private pendingMatch: string | null = null;
+  // The most recently opened auto-match game still awaiting an opponent, for the e2e join hook.
+  private openGameId: string | null = null;
   private friends: AccountRef[] = MOCK_FRIENDS.map((f) => ({ ...f }));
   private incoming: AccountRef[] = MOCK_INCOMING.map((f) => ({ ...f }));
   private outgoing: AccountRef[] = [];
@@ -143,14 +145,16 @@ export class MockGateway implements GatewayClient {
 
   // --- lobby ---
   async lobbyEnqueue(variant: Variant, multipleWords: boolean): Promise<MatchResult> {
-    // Simulate a 10s-style robot substitution, sped up: match found shortly.
+    // The player enters an open game immediately and waits inside it; a robot opponent takes
+    // the empty seat shortly (a sped-up version of the backend's 90–180 s wait), pushing
+    // opponent_joined so the game UI restores from the "searching for opponent" state.
     const id = crypto.randomUUID();
     const g: MockGame = {
       view: {
         id,
         variant,
         dictVersion: 'v1',
-        status: 'active',
+        status: 'open',
         players: 2,
         toMove: 0,
         turnTimeoutSecs: 86400,
@@ -160,7 +164,7 @@ export class MockGateway implements GatewayClient {
         lastActivityUnix: Math.floor(Date.now() / 1000),
         seats: [
           { seat: 0, accountId: ME, displayName: 'You', score: 0, hintsUsed: 0, isWinner: false },
-          { seat: 1, accountId: 'robot', displayName: 'Robo', score: 0, hintsUsed: 0, isWinner: false },
+          { seat: 1, accountId: '', displayName: '', score: 0, hintsUsed: 0, isWinner: false },
         ],
       },
       moves: [],
@@ -170,9 +174,28 @@ export class MockGateway implements GatewayClient {
       chat: [],
     };
     this.games.set(id, g);
-    this.pendingMatch = id;
-    setTimeout(() => this.emit({ kind: 'match_found', gameId: id }), 1400);
-    return { matched: false };
+    this.openGameId = id;
+    // The opponent joins on a timer for manual mock play; the e2e triggers it deterministically
+    // through the __mock hook (see lib/gateway.ts).
+    setTimeout(() => this.fillOpponent(id), 3000);
+    return { matched: false, game: structuredClone(g.view) };
+  }
+
+  // fillOpponent seats a robot in an open game's empty seat and pushes opponent_joined — the
+  // mock of a human or robot taking the seat. A no-op once the game is no longer open.
+  private fillOpponent(id: string): void {
+    const game = this.games.get(id);
+    if (!game || game.view.status !== 'open') return;
+    game.view.status = 'active';
+    game.view.seats[1] = { seat: 1, accountId: 'robot', displayName: 'Robo', score: 0, hintsUsed: 0, isWinner: false };
+    this.emit({ kind: 'opponent_joined', gameId: id, state: this.stateOf(game) });
+  }
+
+  // joinPendingOpponent is the e2e hook (exposed as window.__mock.joinOpponent) to attach the
+  // opponent to the most recently opened game on demand, making the waiting → joined transition
+  // deterministic.
+  joinPendingOpponent(): void {
+    if (this.openGameId) this.fillOpponent(this.openGameId);
   }
 
   async lobbyPoll(): Promise<MatchResult> {
@@ -190,8 +213,8 @@ export class MockGateway implements GatewayClient {
   }
 
   // --- game ---
-  async gameState(gameId: string, _includeAlphabet: boolean): Promise<StateView> {
-    const g = this.game(gameId);
+  // stateOf builds a player's StateView from a mock game (the viewer is always ME).
+  private stateOf(g: MockGame): StateView {
     return {
       game: structuredClone(g.view),
       seat: this.mySeat(g),
@@ -201,6 +224,10 @@ export class MockGateway implements GatewayClient {
     };
   }
 
+  async gameState(gameId: string, _includeAlphabet: boolean): Promise<StateView> {
+    return this.stateOf(this.game(gameId));
+  }
+
   async gameHistory(gameId: string): Promise<History> {
     const g = this.game(gameId);
     return { gameId, moves: structuredClone(g.moves) };

ui/src/lib/model.ts

@@ -5,8 +5,9 @@
 
 export type Variant = 'scrabble_en' | 'scrabble_ru' | 'erudit_ru';
 
-/** Backend game status strings. */
-export type GameStatus = 'active' | 'finished' | string;
+/** Backend game status strings. 'open' is an auto-match game the player has entered
+ *  but which is still waiting for an opponent (the opponent seat has no account). */
+export type GameStatus = 'active' | 'finished' | 'open' | string;
 
 /** Decoded move action kinds (history-independent, see ARCHITECTURE §9.1). */
 export type MoveAction = 'play' | 'pass' | 'exchange' | 'resign' | 'timeout' | string;
@@ -237,8 +238,8 @@ export interface GameList {
 /**
  * A live event delivered over the Subscribe stream. The game events carry the move as a
  * delta — move plus the post-move summary (and the bag size) — the client applies to its
- * cached game without a refetch; match_found / game_started carry the recipient's initial
- * StateView; notify carries the changed lobby payload. The enriched fields are optional
+ * cached game without a refetch; match_found / game_started / opponent_joined carry the
+ * recipient's StateView; notify carries the changed lobby payload. The enriched fields are optional
  * so a client falls back to a refetch when a payload is absent (a gap, or an older peer).
  */
 export type PushEvent =
@@ -248,5 +249,6 @@ export type PushEvent =
   | { kind: 'chat_message'; message: ChatMessage }
   | { kind: 'nudge'; gameId: string; fromUserId: string }
   | { kind: 'match_found'; gameId: string; state?: StateView }
+  | { kind: 'opponent_joined'; gameId: string; state?: StateView }
   | { kind: 'notify'; sub: string; account?: AccountRef; invitation?: Invitation; state?: StateView }
   | { kind: 'heartbeat' };