Fix #513 [Robustness] Autonomous cron supervisor: remove broken skill dependency

The job "Autonomous Cron Supervisor" referenced "tmux-supervisor" skill
which is archived/unavailable. The prompt already contains the full
monitoring protocol, so we remove the skill requirement and let the
agent execute directly using terminal tool.

The supervisor will now:
- Check both `dev` and `timmy` sessions every 7 minutes
- Only Telegram on actionable events (idle, overflow, failure)
- Be silent when all agents are working
- Not conflict with manual supervisor runs

cron/jobs.json

@@ -145,7 +145,7 @@
     {
       "id": "tmux-supervisor-513",
       "name": "Autonomous Cron Supervisor",
-      "prompt": "Load the tmux-supervisor skill and execute the monitoring protocol.\n\nCheck both `dev` and `timmy` tmux sessions for idle panes. Only send Telegram notifications on actionable events (idle, overflow, failure). Be silent when all agents are working.\n\nSteps:\n1. List all tmux sessions (skip 'Alexander')\n2. For each session, list windows and panes\n3. Capture each pane and classify state (idle vs active)\n4. For idle panes: read context, craft context-aware prompt\n5. Send /queue prompts to idle panes\n6. Verify prompts landed\n7. Only notify via Telegram if:\n   - A pane was prompted (idle detected)\n   - A pane shows context overflow (>80%)\n   - A pane is stuck or crashed\n8. If all panes are active: respond with [SILENT]",
+      "prompt": "Execute the tmux session health patrol protocol:\n\nCheck both `dev` and `timmy` tmux sessions for idle panes. Only send Telegram notifications on actionable events (idle, overflow, failure). Be silent when all agents are working.\n\nSteps:\n1. List all tmux sessions (skip 'Alexander')\n2. For each session, list windows and panes\n3. Capture each pane and classify state (idle vs active)\n4. For idle panes: read context, craft context-aware prompt\n5. Send /queue prompts to idle panes\n6. Verify prompts landed\n7. Only notify via Telegram if:\n   - A pane was prompted (idle detected)\n   - A pane shows context overflow (>80%)\n   - A pane is stuck or crashed\n8. If all panes are active: respond with [SILENT]",
       "schedule": {
         "kind": "interval",
         "minutes": 7,
@@ -167,10 +167,7 @@
       "state": "scheduled",
       "paused_at": null,
       "paused_reason": null,
-      "skills": [
-        "tmux-supervisor"
-      ],
-      "skill": "tmux-supervisor"
+      "skills": []
     }
   ],
   "updated_at": "2026-04-13T02:00:00+00:00"