feat(companion): add platform stream passthrough helpers

src/companion/platformClients.test.ts

@@ -25,6 +25,8 @@ function createRuntimeMock(): {
   listCanvasArtifacts: ReturnType<typeof vi.fn>;
   deleteCanvasArtifact: ReturnType<typeof vi.fn>;
   clearCanvasArtifacts: ReturnType<typeof vi.fn>;
+  subscribeAgentStream: ReturnType<typeof vi.fn>;
+  waitForAgentStream: ReturnType<typeof vi.fn>;
 } {
   const connect = vi.fn(async () => undefined);
   const disconnect = vi.fn(() => undefined);
@@ -50,6 +52,8 @@ function createRuntimeMock(): {
   const listCanvasArtifacts = vi.fn(async () => ({ artifacts: [{ id: 'a1' }] }));
   const deleteCanvasArtifact = vi.fn(async () => ({ deleted: true }));
   const clearCanvasArtifacts = vi.fn(async () => ({ cleared: 1 }));
+  const subscribeAgentStream = vi.fn(() => () => undefined);
+  const waitForAgentStream = vi.fn(async () => ({ token: 'streamed' }));
 
   const runtime = {
     connect,
@@ -69,6 +73,8 @@ function createRuntimeMock(): {
     listCanvasArtifacts,
     deleteCanvasArtifact,
     clearCanvasArtifacts,
+    subscribeAgentStream,
+    waitForAgentStream,
   } as unknown as CompanionRuntimeClient;
 
   return {
@@ -90,6 +96,8 @@ function createRuntimeMock(): {
     listCanvasArtifacts,
     deleteCanvasArtifact,
     clearCanvasArtifacts,
+    subscribeAgentStream,
+    waitForAgentStream,
   };
 }
 
@@ -150,6 +158,20 @@ describe('platform companion clients', () => {
     expect(mock.dispose).toHaveBeenCalledOnce();
   });
 
+  it('platform stream helper methods forward to runtime client', async () => {
+    const mock = createRuntimeMock();
+    const client = new AndroidCompanionClient({ runtime: mock.runtime, nodeId: 'android-node' });
+    const streamHandler = vi.fn();
+
+    const unsubscribe = client.subscribeAgentStream(streamHandler);
+    const awaited = await client.waitForAgentStream<{ token: string }>({ timeoutMs: 500 });
+
+    expect(mock.subscribeAgentStream).toHaveBeenCalledWith(streamHandler);
+    expect(mock.waitForAgentStream).toHaveBeenCalledWith({ timeoutMs: 500 });
+    expect(awaited).toEqual({ token: 'streamed' });
+    unsubscribe();
+  });
+
   it('macOS client forwards canvas methods to runtime client', async () => {
     const mock = createRuntimeMock();
     const client = new MacOSCompanionClient({ runtime: mock.runtime, nodeId: 'mac-node' });