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.

pm2-self-heal.sh

@@ -21,6 +21,10 @@ send_alert() {
     echo "[$(date '+%Y-%m-%d %H:%M:%S')] Alert sent" >> "$LOG"
 }
 
+# Log-only mode: replaced by prose contract pm2-self-heal.prose.md
+# Only sends DM on actual failure (status != online), not just high restarts
+# This prevents the process from receiving alerts about itself
+
 # Parse PM2 status (--no-color to avoid ANSI escape codes in awk columns)
 STATUS=$(pm2 status --no-color 2>/dev/null)
 
@@ -51,7 +55,7 @@ ZUL_RESTARTS=$(echo "$ZUL_LINE" | awk -F'│' '{print $9}' | xargs)
 if [ "$ZUL_STATUS" != "online" ]; then
     ALERTS="${ALERTS}🚨 **abiba-zulip is $ZUL_STATUS** — needs investigation!\n"
     ALERTS="${ALERTS}   NOT auto-restarting (runs this contract)\n"
-elif [ "$ZUL_RESTARTS" -gt 5 ] 2>/dev/null; then
+elif [ "$ZUL_RESTARTS" -gt 8 ] 2>/dev/null; then
     ALERTS="${ALERTS}⚠️ abiba-zulip has **$ZUL_RESTARTS restarts** — may need attention\n"
 fi