- Add MAX_CONCURRENT_AGENTS (default: 3) to limit concurrent agents
- Implement acquire_agent_slot() and release_agent_slot() with flock
- Wrap cmd_start, cmd_continue, and cmd_delegate with slot management
- cmd_delegate holds slot until background task completes (fire-and-forget + blocking)
- Add basic concurrency tests to test suite
- cmd_delegate now runs in background with nohup + disown
- Output logged to ~/.kugetsu/logs/delegate-<timestamp>.log
- Added cmd_logs to view recent delegation logs
- Log rotation: logs older than 7 days auto-deleted
Issue #41: #41