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/e2e-prod/scenarios.e2e.test.ts

@@ -16,7 +16,6 @@ describe('e2e-prod: scenarios', () => {
     let runCompleted = false;
 
     const client = makeProdClient(artifact, {
-      planStateStore: null,
       loginEvent: artifact.scenario.event,
     });
 
@@ -25,9 +24,9 @@ describe('e2e-prod: scenarios', () => {
       storeOffer = effect;
     });
     const runtime = await getScenarioRuntime(client);
-    runtime.onRunCompleted = () => {
+    client.effects.onScenarioCompleted(() => {
       runCompleted = true;
-    };
+    });
     await client.auth.loginWithDevice({ region: 'en', language: 'en' });
 
     // The boundary buy uses the paid offer — fund the wallet so the purchase succeeds.
@@ -45,8 +44,8 @@ describe('e2e-prod: scenarios', () => {
     await vi.waitFor(() => expect(notifications.length).toBe(1), { timeout: 10_000 });
     await notifications[0].done();
 
-    // remote_config_override applies, then the store offer surfaces.
     await vi.waitFor(() => expect(storeOffer).toBeDefined(), { timeout: 10_000 });
+    await client.remoteConfig.reload();
     expect(client.remoteConfig.get('spawn_rate', 0)).toBeCloseTo(
       artifact.remoteConfigs.spawnRateOverride,
     );