Fix field name mismatches, add events filter, in-place suppression refresh

- links.html: fix all field name bugs (auto_negotiation→autoneg, full_duplex,
  tx/rx_errors/drops_per_sec→_rate, tx/rx_bytes_per_sec→_rate, poe_total_w/poe_max_w
  computed from ports, renderUnifiSwitches uses top-level updated timestamp)
- suppressions.html: in-place DOM refresh after create/remove (no page reload),
  datalist autocomplete for target names, form reset after submit
- inspector.html: ESC key closes detail panel via lt.keys.on
- index.html: events filter bar with search input + severity pills (All/Critical/Warning),
  MutationObserver re-applies filter after dynamic updates
- style.css: g-section-actions, events-filter-bar, sev-pills layout
- app.js/db.py/monitor.py: carry forward prior session fixes (Promise.allSettled,
  daemon_ok, stale connection handling, double Prometheus call, self.cfg fix)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app.py

@@ -4,6 +4,7 @@ Flask web application serving the monitoring dashboard and suppression
 management UI. Authentication via Authelia forward-auth headers.
 All monitoring and alerting is handled by the separate monitor.py daemon.
 """
+import hashlib
 import ipaddress
 import json
 import logging
@@ -11,6 +12,7 @@ import re
 import threading
 import time
 import uuid
+from datetime import datetime, timezone
 from functools import wraps
 
 from flask import Flask, jsonify, render_template, request
@@ -31,9 +33,10 @@ _AVATAR_COLORS = ['lt-avatar--orange', 'lt-avatar--green', 'lt-avatar--purple',
 
 @app.template_filter('avatar_color')
 def avatar_color_filter(name: str) -> str:
-    return _AVATAR_COLORS[abs(hash(name)) % len(_AVATAR_COLORS)]
+    return _AVATAR_COLORS[int(hashlib.md5(name.encode()).hexdigest(), 16) % len(_AVATAR_COLORS)]
 
 _cfg = None
+_cfg_lock = threading.Lock()
 
 
 @app.context_processor
@@ -54,7 +57,6 @@ _diag_jobs: dict = {}
 _diag_lock = threading.Lock()
 
 
-_last_event_purge = [0.0]  # mutable container so the thread can update it
 
 
 def _purge_old_jobs_loop():
@@ -67,21 +69,12 @@ def _purge_old_jobs_loop():
             stale = [jid for jid, j in _diag_jobs.items() if j.get('created_at', 0) < cutoff]
             for jid in stale:
                 del _diag_jobs[jid]
-            for jid, j in _diag_jobs.items():
+            for jid, j in list(_diag_jobs.items()):
                 if j['status'] == 'running' and j.get('created_at', 0) < stuck_cutoff:
                     j['status'] = 'done'
                     j['result'] = {'status': 'error', 'error': 'Diagnostic timed out (thread crash)'}
                     logger.error(f'Diagnostic job {jid} appeared stuck; marked as errored')
 
-        # Purge old resolved events once per day
-        now = time.time()
-        if now - _last_event_purge[0] > 86400:
-            try:
-                db.purge_old_resolved_events(days=90)
-            except Exception as e:
-                logger.error(f'Daily event purge failed: {e}')
-            _last_event_purge[0] = now
-
 
 _purge_thread = threading.Thread(target=_purge_old_jobs_loop, daemon=True)
 _purge_thread.start()
@@ -90,11 +83,24 @@ _purge_thread.start()
 def _config() -> dict:
     global _cfg
     if _cfg is None:
-        with open('config.json') as f:
-            _cfg = json.load(f)
+        with _cfg_lock:
+            if _cfg is None:
+                with open('config.json') as f:
+                    _cfg = json.load(f)
     return _cfg
 
 
+def _daemon_ok(last_check: str) -> bool:
+    """Return True if monitor last checked within 20 minutes."""
+    if not last_check or last_check == 'Never':
+        return False
+    try:
+        ts = datetime.strptime(last_check, '%Y-%m-%d %H:%M:%S UTC').replace(tzinfo=timezone.utc)
+        return (datetime.now(timezone.utc) - ts).total_seconds() < 1200
+    except Exception:
+        return False
+
+
 # ---------------------------------------------------------------------------
 # Auth helpers
 # ---------------------------------------------------------------------------
@@ -206,11 +212,13 @@ def suppressions_page():
 @require_auth
 def api_status():
     active = db.get_active_events(limit=_PAGE_LIMIT)
+    last_check = db.get_state('last_check', 'Never')
     return jsonify({
         'summary': db.get_status_summary(),
-        'last_check': db.get_state('last_check', 'Never'),
+        'last_check': last_check,
         'events': active,
         'total_active': db.count_active_events(),
+        'daemon_ok': _daemon_ok(last_check),
     })
 
 
@@ -453,7 +461,6 @@ def health():
     try:
         last_check = db.get_state('last_check', '')
         if last_check:
-            from datetime import datetime, timezone
             ts = datetime.strptime(last_check, '%Y-%m-%d %H:%M:%S UTC').replace(tzinfo=timezone.utc)
             age_s = (datetime.now(timezone.utc) - ts).total_seconds()
             if age_s > 1200: