feat: implement admin product management panel with bulk categorization and premium user toggle

flutter/lib/features/admin/presentation/admin_users_panel.dart

@@ -61,6 +61,26 @@ class _AdminUsersPanelState extends ConsumerState<AdminUsersPanel> {
     }
   }
 
+  Future<void> _togglePremium(UserAdmin user) async {
+    final newValue = !user.isPremium;
+    final confirmed = await _confirm(
+      context,
+      newValue ? 'Ge Premium' : 'Ta bort Premium',
+      '${newValue ? 'Ge' : 'Ta bort'} Premium för ${user.username}?',
+    );
+    if (!confirmed || !mounted) return;
+    try {
+      await ref
+          .read(adminRepositoryProvider)
+          .setPremium(user.id, isPremium: newValue);
+      if (!mounted) return;
+      _load();
+    } catch (e) {
+      if (!mounted) return;
+      _showError(e);
+    }
+  }
+
   Future<void> _resetPassword(UserAdmin user) async {
     final confirmed = await _confirm(
       context,
@@ -252,6 +272,7 @@ class _AdminUsersPanelState extends ConsumerState<AdminUsersPanel> {
       itemBuilder: (ctx, i) => _UserTile(
         user: _users[i],
         onChangeRole: () => _changeRole(_users[i]),
+        onTogglePremium: () => _togglePremium(_users[i]),
         onResetPassword: () => _resetPassword(_users[i]),
         onDelete: () => _deleteUser(_users[i]),
       ),
@@ -295,12 +316,14 @@ class _AdminUsersPanelState extends ConsumerState<AdminUsersPanel> {
 class _UserTile extends StatelessWidget {
   final UserAdmin user;
   final VoidCallback onChangeRole;
+  final VoidCallback onTogglePremium;
   final VoidCallback onResetPassword;
   final VoidCallback onDelete;
 
   const _UserTile({
     required this.user,
     required this.onChangeRole,
+    required this.onTogglePremium,
     required this.onResetPassword,
     required this.onDelete,
   });
@@ -356,10 +379,16 @@ class _UserTile extends StatelessWidget {
             switch (action) {
               case 'role':
                 onChangeRole();
+                break;
+              case 'premium':
+                onTogglePremium();
+                break;
               case 'reset':
                 onResetPassword();
+                break;
               case 'delete':
                 onDelete();
+                break;
             }
           },
           itemBuilder: (_) => [
@@ -369,6 +398,10 @@ class _UserTile extends StatelessWidget {
                 user.isAdmin ? 'Nedgradera till user' : 'Uppgradera till admin',
               ),
             ),
+            PopupMenuItem(
+              value: 'premium',
+              child: Text(user.isPremium ? 'Ta bort Premium' : 'Ge Premium'),
+            ),
             const PopupMenuItem(
               value: 'reset',
               child: Text('Återställ lösenord'),