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/api.js

@@ -598,4 +598,5 @@ export const getPendingTasks   = ()           => apiGet('/api/agent-office/tasks
 export const sendAgentCommand  = (agent, action, params={}) => apiPost('/api/agent-office/command', { agent, action, params });
 export const approveAgentTask  = (agent, task_id, approved, feedback='') => apiPost('/api/agent-office/approve', { agent, task_id, approved, feedback });
 export const getAgentStates    = ()           => apiGet('/api/agent-office/states');
+export const getActivityFeed   = (limit=50, offset=0) => apiGet(`/api/agent-office/activity?limit=${limit}&offset=${offset}`);