Fix all admin endpoint response formats

Wrap all admin endpoint responses in { data: ... } to match frontend
expectations and project conventions:
- PATCH /users/:id (enable/disable)
- PATCH /users/:id/role (promote/demote)
- GET /users/:id/activity
- GET /activity
- PATCH /settings

routes/admin.js

@@ -164,8 +164,10 @@ router.patch('/users/:id', async (req, res) => {
     });
 
     res.json({
+      data: {
         user: updatedUser,
         message: isActive ? 'User enabled successfully' : 'User disabled successfully'
+      }
     });
   } catch (error) {
     console.error('Error updating user status:', error);
@@ -249,8 +251,10 @@ router.patch('/users/:id/role', async (req, res) => {
       : 'User demoted to user successfully';
 
     res.json({
+      data: {
         user: updatedUser,
         message
+      }
     });
   } catch (error) {
     console.error('Error updating user role:', error);
@@ -299,6 +303,7 @@ router.get('/users/:id/activity', async (req, res) => {
     ]);
 
     res.json({
+      data: {
         activities,
         pagination: {
           page,
@@ -306,6 +311,7 @@ router.get('/users/:id/activity', async (req, res) => {
           total,
           pages: Math.ceil(total / limit) || 0
         }
+      }
     });
   } catch (error) {
     console.error('Error fetching user activity:', error);
@@ -434,6 +440,7 @@ router.get('/activity', async (req, res) => {
     const activities = await collection.aggregate(pipeline).toArray();
 
     res.json({
+      data: {
         activities,
         pagination: {
           page: validatedPage,
@@ -441,6 +448,7 @@ router.get('/activity', async (req, res) => {
           total,
           pages: Math.ceil(total / validatedLimit) || 0
         }
+      }
     });
   } catch (error) {
     console.error('Error fetching activity:', error);
@@ -1123,8 +1131,10 @@ router.patch('/settings', async (req, res) => {
     const updatedSettings = await getSettings(db);
 
     res.json({
+      data: {
         settings: updatedSettings,
         message: 'Settings updated successfully'
+      }
     });
   } catch (error) {
     console.error('Error updating settings:', error);