feat(companion): add runtime dispose lifecycle helper

src/companion/runtimeClient.ts

@@ -357,6 +357,11 @@ export class CompanionRuntimeClient {
     ws.close(code, reason);
   }
 
+  dispose(code?: number, reason?: string): void {
+    this.disconnect(code, reason);
+    this.clearEventSubscriptions();
+  }
+
   subscribeEvents(handler: CompanionEventHandler): () => void {
     this.eventHandlers.add(handler);
     return () => {