feat: implement sync icon + pricelist badge UI improvements

- Replace text 'Online/Offline' with SVG icons in sync status
- Change sync button to circular arrow icon
- Add dropdown menu with push changes, full sync, and last sync status
- Add pricelist version badge to configuration page
- Load pricelist version via /api/pricelists/latest on DOMContentLoaded

This completes task 1 of Phase 2.5 (UI Improvements) as specified in CLAUDE.md

web/templates/configs.html

@@ -10,6 +10,15 @@
         </button>
     </div>
 
+    <div id="pricelist-badge" class="mt-4 text-sm text-gray-600 hidden">
+        <span class="bg-blue-100 text-blue-800 px-2 py-1 rounded-full">
+            <svg class="w-4 h-4 inline mr-1" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M9 12h6m-6 4h6m2 5H7a2 2 0 01-2-2V5a2 2 0 012-2h5.586a1 1 0 01.707.293l5.414 5.414a1 1 0 01.293.707V19a2 2 0 01-2 2z"></path>
+            </svg>
+            Активный прайслист: <span id="pricelist-version">-</span>
+        </span>
+    </div>
+
     <div id="configs-list">
         <div class="text-center py-8 text-gray-500">Загрузка...</div>
     </div>
@@ -398,7 +407,25 @@ async function loadConfigs() {
     }
 }
 
-document.addEventListener('DOMContentLoaded', loadConfigs);
+document.addEventListener('DOMContentLoaded', function() {
+    loadConfigs();
+
+    // Load latest pricelist version for badge
+    loadLatestPricelistVersion();
+});
+
+async function loadLatestPricelistVersion() {
+    try {
+        const resp = await fetch('/api/pricelists/latest');
+        if (resp.ok) {
+            const pricelist = await resp.json();
+            document.getElementById('pricelist-version').textContent = pricelist.version;
+            document.getElementById('pricelist-badge').classList.remove('hidden');
+        }
+    } catch(e) {
+        console.error('Failed to load pricelist version:', e);
+    }
+}
 </script>
 {{end}}