fix(ui): apply code review feedback on admin_users template accessibility

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

frontend/templates/admin_users.html

@@ -26,7 +26,7 @@
   </div>
 
   <!-- ── Alert banner ───────────────────────────────────────────────────────── -->
-  <div x-show="alert.show" x-transition class="mb-4" role="alert" aria-live="polite">
+  <div x-show="alert.show" x-transition class="mb-4" role="alert" :aria-live="alert.type === 'error' ? 'assertive' : 'polite'">
     <div
       :class="alert.type === 'success'
         ? 'bg-green-50 border-green-400 text-green-800'
@@ -108,7 +108,7 @@
               <a
                 :href="`/files?owner_id=${encodeURIComponent(user.user_id)}`"
                 class="inline-flex items-center gap-1 text-blue-600 hover:underline font-medium"
-                :title="`View documents for ${user.user_id}`"
+                :aria-label="`View ${user.document_count} document${user.document_count !== 1 ? 's' : ''} for ${user.user_id}`"
               >
                 <i class="fas fa-file text-xs" aria-hidden="true"></i>
                 <span x-text="user.document_count"></span>
@@ -284,7 +284,14 @@
           <!-- Blocked toggle -->
           <div class="flex items-center gap-3">
             <label class="relative inline-flex items-center cursor-pointer">
-              <input type="checkbox" x-model="form.is_blocked" class="sr-only peer" id="modal-blocked" />
+              <input
+                type="checkbox"
+                x-model="form.is_blocked"
+                class="sr-only peer"
+                id="modal-blocked"
+                role="switch"
+                :aria-checked="form.is_blocked"
+              />
               <div class="w-10 h-6 bg-gray-200 peer-focus:ring-2 peer-focus:ring-blue-400 rounded-full peer peer-checked:bg-red-500 after:content-[''] after:absolute after:top-[2px] after:left-[2px] after:bg-white after:rounded-full after:h-5 after:w-5 after:transition-all peer-checked:after:translate-x-4"></div>
             </label>
             <label for="modal-blocked" class="text-sm font-medium text-gray-700">
@@ -527,7 +534,7 @@ function adminUsersApp() {
     userInitials(userId) {
       if (!userId) return '?';
       // Try to get initials from email or username
-      const parts = userId.split(/[@._\-\s]+/);
+      const parts = userId.split(/[@._\s-]+/);
       return parts.slice(0, 2).map(p => p[0]?.toUpperCase() || '').join('') || userId[0].toUpperCase();
     },