Fix general settings route and req.user references

- Update frontend settings service to use correct /api/admin/settings/general route
- Fix all req.user to req.admin references in adminSettings.js
- Ensures settings can be saved without authentication errors

backend/src/routes/adminEmail.js

@@ -86,7 +86,7 @@ router.post('/config', [
     await logActivity('email_config_updated', 
       { smtp_host, from_email }, 
       null, 
-      { type: 'admin', id: req.user.id, name: req.user.username }
+      { type: 'admin', id: req.admin.id, name: req.admin.username }
     );
 
     res.json({ message: 'Email configuration updated successfully' });
@@ -224,8 +224,8 @@ router.put('/templates/:key', [
     await db('activity_logs').insert({
       activity_type: 'email_template_updated',
       actor_type: 'admin',
-      actor_id: req.user.id,
-      actor_name: req.user.username,
+      actor_id: req.admin.id,
+      actor_name: req.admin.username,
       metadata: JSON.stringify({ template_key: req.params.key })
     });