Server-side scenario execution: thin effects client replaces local engine

- engine/ (DagWalker, sessions, IndexedDbPlanStore) deleted; server owns the graph
- trigger/callback/counter carry PendingEffect; GET /sdk/v1/scenarios/pending polled
  (30s jittered heartbeat paused on hidden tab + wait-deadline timers)
- client.effects public API unchanged (done/buy/dismiss/end/claim/battlepass/quest)
- planStateStore removed; loginEvent kept; reconcile() makes server the source of truth
- generated models regenerated; skills/README/CHANGELOG updated

test/AuthService.test.ts

@@ -30,7 +30,7 @@ describe('AuthService', () => {
 
     const response = await client.auth.loginWithDevice({ region: 'us', language: 'en' });
 
-    expect(fetchMock).toHaveBeenCalledTimes(8);
+    expect(fetchMock).toHaveBeenCalledTimes(9);
     const [url, init] = fetchMock.mock.calls[0];
     expect(url).toContain('/sdk/v1/authorization/device');
     const body = JSON.parse(init.body);
@@ -46,10 +46,9 @@ describe('AuthService', () => {
       '/sdk/v1/player/information',
       '/sdk/v1/stores',
       '/sdk/v1/catalog',
+      '/sdk/v1/scenarios/pending',
       '/sdk/v1/scenarios/trigger',
-      // The login event invalidates the warmed profile → refetch.
       '/sdk/v1/player/information',
-      // Sync engine baseline poll, fired right after login.
       '/sdk/v1/sync',
     ]);
   });