Dynamic resolved count, host search filter, lt-divider for UniFi section

- db.py: add resolved_24h to get_status_summary() so each /api/status
  poll carries the fresh 24h resolved count
- app.js: wire stat-resolved-val to update from summary.resolved_24h
  so the Resolved 24h card stays accurate after auto-refresh
- index.html: add lt-toolbar/lt-search above host grid for quick
  client-side host filtering by name
- links.html: replace custom unifi-section-header div with lt-divider
- style.css: remove unused .unifi-section-header rules

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

static/app.js

@@ -92,8 +92,10 @@ function updateStatusBar(summary, lastCheck, daemonOk) {
   // Update stat cards
   const scCrit = document.getElementById('stat-critical-val');
   const scWarn = document.getElementById('stat-warning-val');
+  const scRes  = document.getElementById('stat-resolved-val');
   if (scCrit) scCrit.textContent = critCount;
   if (scWarn) scWarn.textContent = warnCount;
+  if (scRes && summary.resolved_24h != null) scRes.textContent = summary.resolved_24h;
   const statCritCard = document.getElementById('stat-critical');
   if (statCritCard) statCritCard.classList.toggle('lt-stat-card--alert', critCount > 0);