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

server/index.ts

@@ -156,6 +156,17 @@ app.get('/api/games/:id/map', (req, res) => {
   res.json({ regions: buildRegionMap(game) });
 });
 
+// Delete a saved game entirely. Fast, non-LLM. 404 if it doesn't exist; on
+// success broadcast an SSE `error` to any other open tab watching it so it
+// returns home (see the `event: error` handling in src/lib/sse.ts).
+app.delete('/api/games/:id', (req, res) => {
+  const id = req.params.id;
+  const removed = db.delete(id);
+  if (!removed) return res.status(404).json({ error: 'game not found' });
+  broadcast(id, 'error', { message: 'game deleted' });
+  res.json({ deleted: true });
+});
+
 // Queue a free-text player action onto the pending round. No LLM call and no
 // turn advance — the round is only committed (in one turn) by "Jump forward".
 app.post('/api/games/:id/action', (req, res) => {