feat(daemon): Add circuit breaker for stuck agents (gt-72cqu)

- Add Refinery monitoring to daemon heartbeat (ensureRefineriesRunning)
- Add circuit breaker: agents marked dead by checkStaleAgents() are
  now force-killed and restarted, even if Claude process is alive
- Fixes zombie Claude sessions that werent updating their bead state

The circuit breaker flow:
1. Agent gets stuck (stops updating bead state)
2. After 15 minutes: checkStaleAgents() marks bead as dead
3. On next heartbeat: ensure*Running() sees state=dead
4. Force-kill session and restart fresh

Generated with Claude Code

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

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