test(companion): add event surface snapshot integration coverage

docs/plans/state.json

@@ -1108,6 +1108,17 @@
       ],
       "test_status": "pnpm test:run src/companion/platformClients.integration.test.ts src/companion/platformClients.test.ts src/companion/runtimeClient.test.ts src/companion/heartbeatLoop.test.ts + pnpm typecheck passing"
     },
+    "companion-platform-event-surface-snapshot-integration-coverage": {
+      "status": "completed",
+      "date": "2026-02-17",
+      "updated": "2026-02-17",
+      "summary": "Added platform integration coverage for `getEventSurfaceSnapshot()` across active subscription/waiter and teardown states.",
+      "files_modified": [
+        "src/companion/platformClients.integration.test.ts",
+        "docs/plans/state.json"
+      ],
+      "test_status": "pnpm test:run src/companion/platformClients.integration.test.ts src/companion/platformClients.test.ts src/companion/runtimeClient.test.ts src/companion/heartbeatLoop.test.ts + pnpm typecheck passing"
+    },
     "companion-runtime-wait-for-idle-nonfinite-validation-coverage": {
       "status": "completed",
       "date": "2026-02-17",

src/companion/platformClients.integration.test.ts

@@ -228,6 +228,34 @@ describe('platform clients integration', () => {
     expect(client.eventSubscriptionCount).toBe(0);
   });
 
+  it('platform getEventSurfaceSnapshot reflects subscription and waiter lifecycle', async () => {
+    if (!LISTEN_ALLOWED) {
+      return;
+    }
+
+    const runtime = createRuntime();
+    const client = new IOSCompanionClient({ runtime, nodeId: 'ios-event-snapshot-e2e' });
+
+    const unsubscribe = client.subscribeEvents(() => undefined);
+    const pending = client.waitForAnyEvent(['agent.stream'], { timeoutMs: 10_000 }).catch(() => undefined);
+
+    expect(client.getEventSurfaceSnapshot()).toEqual({
+      knownEventNames: ['agent.stream', 'agent.typing', 'context_warning'],
+      eventSubscriptionCount: 2,
+      pendingEventWaitCount: 1,
+    });
+
+    client.clearEventSubscriptions();
+    await pending;
+    expect(client.getEventSurfaceSnapshot()).toEqual({
+      knownEventNames: ['agent.stream', 'agent.typing', 'context_warning'],
+      eventSubscriptionCount: 0,
+      pendingEventWaitCount: 0,
+    });
+
+    unsubscribe();
+  });
+
   it('platform connected reflects runtime connection lifecycle', async () => {
     if (!LISTEN_ALLOWED) {
       return;