fix(offline): delete a finished local game from the device, not the network

The lobby's finished-game delete (hide) always called gateway.hideGame; for a
local (offline) game the transport kill switch refused it, so it toasted and the
game stayed. Route by id: a local game is removed from the device store + the
source cache (LocalSource.delete), an online game still hides on the backend.

ui/src/lib/gamesource.ts

@@ -40,6 +40,7 @@ export const localSource = {
   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)),
   // 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) => {
@@ -53,7 +54,7 @@ export const localSource = {
       unsub();
     };
   },
-} satisfies GameLoopSource & Pick<LocalSource, 'events' | 'create' | 'list'>;
+} satisfies GameLoopSource & Pick<LocalSource, 'events' | 'create' | 'list' | 'delete'>;
 
 /**
  * gameSource returns the source that runs the game with the given id: the local engine for a local

ui/src/lib/localgame/source.list.test.ts

@@ -65,6 +65,14 @@ describe('LocalSource.list', () => {
     expect(g.seats[1].accountId).not.toBe('acct-42'); // the robot keeps a synthetic id
   });
 
+  it('delete removes a stored local game from the list', async () => {
+    const src = new LocalSource();
+    await src.create(opts('local:x', 5n));
+    expect((await src.list()).map((g) => g.id)).toContain('local:x');
+    await src.delete('local:x');
+    expect((await src.list()).map((g) => g.id)).not.toContain('local:x');
+  });
+
   it('reconstructs a game persisted by a previous session (not in the source cache)', async () => {
     // Seed the store via one source, then list from a fresh source whose in-memory cache is empty.
     await new LocalSource().create(opts('local:old', 7n));

ui/src/lib/localgame/source.ts

@@ -10,7 +10,7 @@
 
 import { LocalGame, type LocalMove } from './engine';
 import { serializeGame, replayGame, type LocalGameRecord, type Seat as LocalSeat } from './serialize';
-import { getLocalGame, saveLocalGame, listLocalGames } from './store';
+import { getLocalGame, saveLocalGame, listLocalGames, deleteLocalGame } from './store';
 import { RULESETS } from './ruleset';
 import { getDawg } from '../dict';
 import { LOCAL_ID_PREFIX, isLocalGameId } from './id';
@@ -151,6 +151,14 @@ export class LocalSource implements GameLoopSource {
     return views;
   }
 
+  /** delete removes a local game from the store and the in-memory cache — the offline lobby's
+   *  finished-game delete. Best-effort: a failed store delete still drops it from this session. */
+  async delete(gameId: string): Promise<void> {
+    this.live.delete(gameId);
+    this.listeners.delete(gameId);
+    await deleteLocalGame(gameId);
+  }
+
   async gameState(gameId: string): Promise<StateView> {
     return this.stateView(await this.load(gameId));
   }

ui/src/screens/Lobby.svelte

@@ -14,7 +14,7 @@
   import { getLobby, setLobby } from '../lib/lobbycache';
   import { preloadGames } from '../lib/preload';
   import { kickDictPreload, offlineMode } from '../lib/offline.svelte';
-  import { localSource } from '../lib/gamesource';
+  import { localSource, isLocalGameId } from '../lib/gamesource';
   import { gamePhase, groupGames, orderedSeats, scoreStanding, shouldBlink, type LobbyPhase } from '../lib/lobbysort';
   import type { AccountRef, GameView, Invitation } from '../lib/model';
   import { VARIANT_FLAG, VARIANT_RULES } from '../lib/variants';
@@ -216,7 +216,11 @@
     games = games.filter((g) => g.id !== id); // optimistic; the backend already filters it out
     setLobby({ games, invitations, incoming, atGameLimit });
     try {
-      await gateway.hideGame(id);
+      // A local (offline) game is deleted from the device store; an online game is hidden on the
+      // backend. Routing by id keeps the delete off the network for a local game (the transport
+      // kill switch would otherwise refuse it offline).
+      if (isLocalGameId(id)) await localSource.delete(id);
+      else await gateway.hideGame(id);
     } catch (e) {
       games = prev;
       setLobby({ games, invitations, incoming, atGameLimit });