When the daemon checks if Deacon/Witness is running, it first checks the
agent bead state. If this check fails (bead not found, JSON parse error,
or stale state), it would previously attempt to restart the session -
even if the tmux session was perfectly healthy.
This caused "session already exists" errors when:
1. Agent bead state couldn't be read (prefix mismatch, missing bead)
2. But the tmux session was actually running with Claude active
Fix: Add a tmux session health check as fallback before attempting restart.
If the session exists AND Claude is running in it, skip the restart and
log that we're preserving the healthy session despite stale bead state.
This maintains ZFC compliance (still trusts agent bead as primary source)
while adding a defensive check to prevent unnecessary session kills.
Fixes#63🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
a83d5c6e0b