feat(zulip-health): Gen 3 — stuck detection, proactive queue recovery, restart debounce

- Health endpoint now reports stuck:bool + idle_seconds + last_activity_time
- Extension re-registers queue after 30min idle (even without BAD_EVENT_QUEUE_ID)
- Broadened queue expiry detection (matches deregistered, invalid queue, etc.)
- zulip-monitor.sh detects stuck:true + enforces 300s restart debounce
- Prevents silent death where bot shows connected:true but processes 0 messages

Fixes the 'getting stuck and restarts once and for all' issue.

zulip-health.prose.md

@@ -45,6 +45,8 @@ const health = await fetch("http://localhost:9200/health").then(r => r.json());
 | Field | Healthy | Critical |
 |-------|---------|----------|
 | `connected` | `true` | `false` |
+| `stuck` | `false` | `true` (Gen 3) |
+| `idle_seconds` | < 1800 | >= 1800 |
 | `last_error` | `null` | non-null string |
 | `retry_count` | 0-2 | 3+ |
 | `queue_id` | non-null string | `null` |
@@ -78,6 +80,7 @@ grep -a "Finalized\|Failed to finalize" /root/.pm2/logs/abiba-zulip-out.log | ta
 | Condition | Action |
 |-----------|--------|
 | `connected: false` | `pm2 restart abiba-zulip` |
+| `stuck: true` | `pm2 restart abiba-zulip` (Gen 3) |
 | `retry_count >= 3` | `pm2 restart abiba-zulip` |
 | `last_error` set | Log and monitor |
 | Crash loop >10/h | Alert user |
@@ -137,6 +140,11 @@ ssh root@192.168.68.122 "grep -E 'Finalized|Failed to finalize|Replied to' ~/.he
 | `Failed to finalize` > 50% | Check PATCH API, Zulip server |
 | Response empty/short | Check A2A endpoint / LiteLLM model |
 
+## Restart Debounce (Gen 3)
+
+All restart actions MUST debounce: minimum 300s between restarts.
+Track via `/tmp/zulip-monitor-debounce` (unix timestamp of last restart).
+
 ---
 
 ## Platform C: Agent Zero (kagentz — CT 105)
@@ -233,3 +241,17 @@ If any bot is processing >50 bot-originated messages in 15min → 🟡 Warning.
 
 All diagnostics logged to `/root/zulip-health-monitor.log` with timestamps.
 Critical alerts sent as relay messages to user.
+
+## Gen 3 Changes (2026-06-28)
+
+### Problem
+- Bot shows `connected: true` but silently stops processing messages (Zulip event queue expires without BAD_EVENT_QUEUE_ID error)
+- `messages_processed=0` for 45+ min while health endpoint reports healthy
+- Multiple overlapping monitors cause restart death spiral
+
+### Fixes
+1. **Stuck detection**: Health endpoint now reports `stuck: bool`, `idle_seconds`, `last_activity_time`
+2. **Proactive queue recovery**: Re-register queue after 30min of no events (even without BAD_EVENT_QUEUE_ID)
+3. **Monitor stuck awareness**: `zulip-monitor.sh` restarts on `stuck: true` not just `connected: false`
+4. **Restart debounce**: 300s minimum between restarts (via `/tmp/zulip-monitor-debounce`)
+5. **Broader queue expiry detection**: Matches multiple error message patterns