move pi-mono into companion-cloud as apps/companion-os

- Copy all pi-mono source into apps/companion-os/
- Update Dockerfile to COPY pre-built binary instead of downloading from GitHub Releases
- Update deploy-staging.yml to build pi from source (bun compile) before Docker build
- Add apps/companion-os/** to path triggers
- No more cross-repo dispatch needed

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/coding-agent/src/core/event-bus.ts

@@ -0,0 +1,33 @@
+import { EventEmitter } from "node:events";
+
+export interface EventBus {
+  emit(channel: string, data: unknown): void;
+  on(channel: string, handler: (data: unknown) => void): () => void;
+}
+
+export interface EventBusController extends EventBus {
+  clear(): void;
+}
+
+export function createEventBus(): EventBusController {
+  const emitter = new EventEmitter();
+  return {
+    emit: (channel, data) => {
+      emitter.emit(channel, data);
+    },
+    on: (channel, handler) => {
+      const safeHandler = async (data: unknown) => {
+        try {
+          await handler(data);
+        } catch (err) {
+          console.error(`Event handler error (${channel}):`, err);
+        }
+      };
+      emitter.on(channel, safeHandler);
+      return () => emitter.off(channel, safeHandler);
+    },
+    clear: () => {
+      emitter.removeAllListeners();
+    },
+  };
+}