fix(ui): resolve hidden class vs style.display conflict, polish toggle buttons

style.display='block'. All panel show/hide now uses classList.
- Fix admin badge/panel not showing in user menu (same root cause).
- Fix profile page main-content/auth-error panels (same root cause).
- Add hidden class to admin-setup-panel in login.html for consistency.
- Remove redundant .admin-setup-panel{display:none} CSS rule.
- Polish view toggle buttons: tighter gap, smaller size, subtler shadow.

static/js/views/profile/profile.js

@@ -84,8 +84,8 @@ async function init() {
     } catch (oidcErr) {
     }
 
-    document.getElementById('loading').style.display = 'none';
-    document.getElementById('main-content').style.display = 'block';
+    document.getElementById('loading').classList.add('hidden');
+    document.getElementById('main-content').classList.remove('hidden');
   } catch (e) {
     console.error(e);
     showError();
@@ -93,8 +93,8 @@ async function init() {
 }
 
 function showError() {
-  document.getElementById('loading').style.display = 'none';
-  document.getElementById('auth-error').style.display = 'block';
+  document.getElementById('loading').classList.add('hidden');
+  document.getElementById('auth-error').classList.remove('hidden');
 }
 
 async function changePassword(e) {