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/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));
   }