fix(vscode): wire native notifications from runtime events

packages/vscode/webview/api/notifications.ts

@@ -0,0 +1,23 @@
+import type { NotificationPayload, NotificationsAPI } from '@openchamber/ui/lib/api/types';
+import { sendBridgeMessage } from './bridge';
+
+type NotifyResponse = { shown?: boolean };
+
+export const createVSCodeNotificationsAPI = (): NotificationsAPI => ({
+  async notifyAgentCompletion(payload?: NotificationPayload): Promise<boolean> {
+    try {
+      const response = await sendBridgeMessage<NotifyResponse>('notifications:notify', { payload });
+      return Boolean(response?.shown);
+    } catch {
+      return false;
+    }
+  },
+
+  async canNotify(): Promise<boolean> {
+    try {
+      return await sendBridgeMessage<boolean>('notifications:can-notify');
+    } catch {
+      return false;
+    }
+  },
+});