Backend: _get_agent_health() with CPU/Memory/Threads from ps, get_agent_tasks() reads tasks.json. API: GET /api/agents/{id}/health + /tasks. Frontend: Health metrics block in Overview tab (CPU, Memory bar, Threads), Tasks tab with status-colored task list.
Backend: _get_chat_history() reads JSONL sessions. API: GET /api/agents/{id}/chat-history. Frontend: Chat History tab shows session list with title, model, message count. Click to open session in chat panel.
