fix: suppress 404 errors for optional MBE models endpoint and defer user loading

- loadMbeModels no longer logs console.error for 404 (endpoint may not exist)
- loadUsers removed from onMounted - only called after admin login
- Prevents 401 errors on page load before user has authenticated
- Users tab now only loads data after successful login

src/views/AdminView.vue

@@ -1368,14 +1368,13 @@ async function loadMbeModels() {
     }
   } catch (e) {
     // Silently fail - models list is optional
-    console.error('Failed to load MBE models:', e)
   }
 }
 
 onMounted(async () => { 
   loadServiceUrls()
   await loadMbeModels()
-  await Promise.all([loadDashboard(), loadUsers(), loadShares(), loadSettings()])
+  await Promise.all([loadDashboard(), loadShares(), loadSettings()])
   await Promise.all([testCoreApi(), testMarkbase(), testMbe(), testProxy(), testWorker()])
 })
 </script>