feat: remove a saved game & redirect on missing/deleted game (#20)

- DELETE /api/games/:id route + Db.delete() (404 when absent)
- PresetPicker: per-saved-game trash button + confirm dialog (Cancel/Delete)
- App: runDeleteGame; useSse onError -> goHome on 'deleted'/'not found'
  (a deleted/missing game now returns the live tab and any deep link home)
- DeleteGameResponse in shared/protocol.ts; api.deleteGame()
- unit test (Db.delete) + 2 e2e tests (home-screen delete; in-flight delete
  returns the active tab home and a fresh deep link lands on home)
- version 0.7.0 -> 0.8.0 + changelog

Fixes #20

src/lib/api.ts

@@ -7,6 +7,7 @@ import type {
   AddDiplomacyResponse,
   AdvisorResponse,
   CreateGameResponse,
+  DeleteGameResponse,
   GameSummary,
   RemoveQueueItemResponse,
   TurnResponse,
@@ -33,6 +34,9 @@ export const api = {
       body: JSON.stringify({ presetId, playerNationId }),
     }),
   getGame: (id: string) => req<{ game: GameState }>(`/api/games/${id}`),
+  // Delete a saved game entirely. Fast, non-LLM. Returns { deleted: true }.
+  deleteGame: (id: string) =>
+    req<DeleteGameResponse>(`/api/games/${id}`, { method: 'DELETE' }),
   // Every saved game as a lightweight summary, newest-updated first (for the
   // home screen's "Saved games" section / resume affordances).
   listGames: () => req<{ games: GameSummary[] }>('/api/games'),