This commit addresses multiple issues in the Docker/host agent removal flow:
Agent Stop Fix:
- Add systemctl stop command after agent acknowledgement to prevent systemd restart
- Previous behavior: agent disabled but systemd immediately restarted it (Restart=always)
- New behavior: agent disables itself, sends ack, then stops systemd service completely
UX Improvements:
- Add real-time elapsed time counter during removal wait
- Show progress indicators prominently (no longer hidden in dropdown)
- Display expected time range (30-60 seconds) and last heartbeat
- Auto-show timeout warning after 2 minutes with actionable "Force remove" button
- Add contextual help explaining what's happening at each stage
Security Enhancement:
- Automatically revoke API tokens when removing Docker/host agents
- Previous behavior: tokens remained valid after agent removal
- New behavior: tokens are revoked and persisted immediately on removal
- Prevents removed agents from re-authenticating with old credentials