Rework device type view to group by deviceType tag

- /api/devices now groups hosts by deviceType tag instead of host group;
  hosts without the tag are skipped
- /api/detail device lookup filters by deviceType tag instead of groupid
- getTag() is now case-insensitive on the tag name
- Removed selectHostGroups from fetchKFCData (no longer needed)
- Frontend: hex id and Zabbix deep-link use deviceType instead of groupid
- Smaller hex label (1.2rem) for device type view via hex-item--device class
- Skip DOM re-render on auto-refresh when data is unchanged (lastDataKey diff)

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

public/app.js

@@ -36,6 +36,7 @@ let refreshTimer     = null;
 let zabbixUrl        = '';
 let customerTagValue = 'QWE';
 let hasRendered      = false;
+let lastDataKey      = null;
 const REFRESH_MS     = 30_000;
 
 /* ── Boot ────────────────────────────────────────────────────────────────── */
@@ -58,6 +59,7 @@ function initControls() {
       btn.classList.add('active');
       currentView = btn.dataset.view;
       hasRendered = false;
+      lastDataKey = null;
       loadData();
     });
   });
@@ -87,8 +89,12 @@ async function loadData() {
       apiFetch(endpoint),
       apiFetch('/api/stats').catch(() => ({})),
     ]);
-    renderCountryColumns(items, stats);
-    updateSummary(items);
+    const key = JSON.stringify({ items, stats });
+    if (key !== lastDataKey) {
+      lastDataKey = key;
+      renderCountryColumns(items, stats);
+      updateSummary(items);
+    }
     setLastUpdated(new Date());
     hasRendered = true;
   } catch (e) {
@@ -195,13 +201,13 @@ function buildHex(item) {
   const sev    = item.severity;
   const info   = sevInfo(sev);
   const label  = item.location || item.name || '—';
-  const id     = item.location || item.groupid || '';
+  const id     = item.location || item.deviceType || '';
   const type   = item.location ? 'restaurant' : 'device';
   const issues = item.problemCount || 0;
   const hosts  = item.hostCount   || 0;
 
   const el = document.createElement('div');
-  el.className = `hex-item sev-${sev}`;
+  el.className = `hex-item sev-${sev}${type === 'device' ? ' hex-item--device' : ''}`;
   el.style.background = info.color;
   el.title = `${label}\n${hosts} host(s) · ${issues} issue(s) · ${info.label}\n\nClick: details   Double-click: open in Zabbix`;
 
@@ -364,10 +370,12 @@ function buildZabbixProblemsUrl(type, id) {
     p.push(`tags[1][value]=${encodeURIComponent(id)}`);
     p.push(`tags[1][operator]=1`);
   } else {
-    p.push(`groupids[]=${encodeURIComponent(id)}`);
     p.push(`tags[0][tag]=customer`);
     p.push(`tags[0][value]=${encodeURIComponent(customerTagValue)}`);
     p.push(`tags[0][operator]=1`);
+    p.push(`tags[1][tag]=deviceType`);
+    p.push(`tags[1][value]=${encodeURIComponent(id)}`);
+    p.push(`tags[1][operator]=1`);
   }
 
   return `${zabbixUrl}/zabbix.php?${p.join('&')}`;