fix(companion): validate waitForIdle timeout option

src/companion/runtimeClient.test.ts

@@ -661,6 +661,16 @@ describe('CompanionRuntimeClient', () => {
     );
   });
 
+  it('waitForIdle validates timeoutMs option', () => {
+    const client = new CompanionRuntimeClient({
+      url: 'ws://127.0.0.1:1',
+    });
+
+    expect(() => client.waitForIdle({ timeoutMs: 0 })).toThrow(
+      'timeoutMs must be a positive number',
+    );
+  });
+
   it('waitForIdle resolves after pending event waiters are cleared', async () => {
     const client = new CompanionRuntimeClient({
       url: 'ws://127.0.0.1:1',