refactor(rbac): remove local ad permissions and role assignments

- Remove local ad related permissions from permissions.dart
- Remove local ad related permissions from role_permissions.dart
- Update guest and admin role permissions accordingly

Author: fulleni

lib/src/rbac/permissions.dart

@@ -73,12 +73,6 @@ abstract class Permissions {
   static const String userPreferenceBypassLimits =
       'user_preference.bypass_limits';
 
-  // Local Ad Permissions
-  static const String localAdCreate = 'local_ad.create';
-  static const String localAdRead = 'local_ad.read';
-  static const String localAdUpdate = 'local_ad.update';
-  static const String localAdDelete = 'local_ad.delete';
-
   // General System Permissions
   static const String rateLimitingBypass = 'rate_limiting.bypass';
 

lib/src/rbac/role_permissions.dart

@@ -14,7 +14,6 @@ final Set<String> _appGuestUserPermissions = {
   Permissions.userContentPreferencesReadOwned,
   Permissions.userContentPreferencesUpdateOwned,
   Permissions.remoteConfigRead,
-  Permissions.localAdRead,
   // Allows a user to update their own User object. This is essential for
   // features like updating the `feedActionStatus` (e.g., when a user
   // dismisses an in-feed prompt, etc). The endpoint handler ensures only
@@ -90,11 +89,6 @@ final Set<String> _dashboardAdminPermissions = {
   Permissions.remoteConfigUpdate,
   Permissions.remoteConfigDelete,
   Permissions.userPreferenceBypassLimits,
-  // Added localAd CRUD permissions for admins
-  Permissions.localAdCreate,
-  Permissions.localAdRead,
-  Permissions.localAdUpdate,
-  Permissions.localAdDelete,
 };
 
 /// Defines the mapping between user roles (both app and dashboard) and the