feat(agent-office): notification badges + CEO desk document panel + telegram test

- Add notification state management with badge counts in useAgentManager
- Render exclamation badge on agent sprites (separate from status icons)
- Add CEO desk document icon with click-to-open activity panel
- Create DocumentPanel with unified activity feed + per-agent detail tabs
- Add telegram test button to stock agent ChatPanel
- Remove TaskHistory + bottom toolbar (replaced by DocumentPanel)
- Add getActivityFeed API helper

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

src/pages/agent-office/canvas/AgentSprite.js

@@ -6,6 +6,7 @@ export class AgentSprite {
     this.waypoints = waypoints;
     this.state = 'idle';
     this.detail = '';
+    this.notificationCount = 0;
 
     const deskKey = `${agentId}_desk`;
     const desk = waypoints[deskKey] || { x: 5, y: 3 };
@@ -20,6 +21,10 @@ export class AgentSprite {
     this._moveSpeed = 0.05;
   }
 
+  setNotification(count) {
+    this.notificationCount = count;
+  }
+
   setState(newState, detail = '') {
     this.state = newState;
     this.detail = detail;