feat(companion): add clearEventSubscriptions helper

src/companion/runtimeClient.test.ts

@@ -196,6 +196,28 @@ describe('CompanionRuntimeClient', () => {
     expect(streamHandler).toHaveBeenCalledTimes(1);
   });
 
+  it('clears all event subscriptions', () => {
+    const client = new CompanionRuntimeClient({
+      url: 'ws://127.0.0.1:1',
+    });
+    const handlerA = vi.fn();
+    const handlerB = vi.fn();
+    client.subscribeEvents(handlerA);
+    client.subscribeEvent('agent.stream', handlerB);
+    client.clearEventSubscriptions();
+
+    (client as unknown as { handleMessage: (raw: string) => void }).handleMessage(
+      JSON.stringify({
+        id: 50,
+        event: 'agent.stream',
+        data: { token: 'cleared' },
+      }),
+    );
+
+    expect(handlerA).not.toHaveBeenCalled();
+    expect(handlerB).not.toHaveBeenCalled();
+  });
+
   it('waitForEvent resolves using optional predicate filter', async () => {
     const client = new CompanionRuntimeClient({
       url: 'ws://127.0.0.1:1',