feat(companion): add waitForEvent runtime helper

src/companion/runtimeClient.test.ts

@@ -187,6 +187,48 @@ describe('CompanionRuntimeClient', () => {
     expect(streamHandler).toHaveBeenCalledTimes(1);
   });
 
+  it('waitForEvent resolves using optional predicate filter', async () => {
+    const client = new CompanionRuntimeClient({
+      url: 'ws://127.0.0.1:1',
+    });
+
+    const awaited = client.waitForEvent<{ seq: number }>('agent.stream', {
+      timeoutMs: 2000,
+      predicate: (data) => data.seq === 2,
+    });
+
+    (client as unknown as { handleMessage: (raw: string) => void }).handleMessage(
+      JSON.stringify({
+        id: 48,
+        event: 'agent.stream',
+        data: { seq: 1 },
+      }),
+    );
+    (client as unknown as { handleMessage: (raw: string) => void }).handleMessage(
+      JSON.stringify({
+        id: 49,
+        event: 'agent.stream',
+        data: { seq: 2 },
+      }),
+    );
+
+    await expect(awaited).resolves.toEqual({ seq: 2 });
+  });
+
+  it('waitForEvent rejects on timeout', async () => {
+    vi.useFakeTimers();
+    const client = new CompanionRuntimeClient({
+      url: 'ws://127.0.0.1:1',
+    });
+
+    const awaited = expect(
+      client.waitForEvent('agent.stream', { timeoutMs: 100 }),
+    ).rejects.toThrow('Timed out waiting for event agent.stream');
+    await vi.advanceTimersByTimeAsync(100);
+    await awaited;
+    vi.useRealTimers();
+  });
+
   it('connects and performs node registration + capability discovery', async () => {
     if (!LISTEN_ALLOWED) {
       return;