feat(tmux-agent-orchestrate-monitor): integrate watchdog pattern as skill

Moved /tmp/subscriber-watchdog.sh → skills/tmux-agent-orchestrate-monitor/scripts/watchdog.sh
(skill-managed lifecycle, no longer lives outside workspace).

Added lib.sh::start_watchdog() helper:
- Spawns watchdog as background nohup process
- Writes watchdog log to .hermes/jobs/<JID>.watchdog.log
- Returns watchdog PID via stdout

Wired create_session.sh --submit-job to auto-start watchdog after JOB registration.

Fixes:
- Bug: registry.py get first-line parse was fragile (empty status → infinite loop)
  → Now uses python3 json.load for robust parsing
- Bug: old path skills/delegate-job/scripts/job_subscriber.py hardcoded
  → Now uses skills/tmux-agent-orchestrate-delegate-job/scripts/job_subscriber.py

Verified on isolated server -L agy-watchdog-skill-test (kill-server after):
- Syntax check PASS
- E2E: register job → start watchdog → publish completed → watchdog exits
- Global skill non-interference verified
- Main isolated server -L multi-agent-canary untouched

skills/tmux-agent-orchestrate-create/scripts/create_session.sh

@@ -263,6 +263,8 @@ echo "tmux session: $SESSION_NAME (pane pid $PANE_PID, cmd $PANE_CMD, cwd $PANE_
 if [ -n "$DELEGATE_JOB_ID" ]; then
   echo "delegate job: $DELEGATE_JOB_ID"
   delegate_publish_event "$DELEGATE_JOB_ID" started "tmux-agent-orchestrate session created"
+  WD_PID=$(start_watchdog "$DELEGATE_JOB_ID" "$WORKSPACE")
+  echo "watchdog PID: $WD_PID"
 fi
 echo "agent-sessions.yaml updated"
 echo