Add privilege management system with related migrations and guards

- Introduced a new `PrivilegesModule` to manage user privileges and access control.
- Added `RequirePrivilege` decorator to enforce privilege checks on controller handlers.
- Implemented `PrivilegesGuard` to handle authorization based on user privileges.
- Created database migrations for `privileges`, `privilege_keys`, and `privilege_details` tables.
- Updated user model to include `is_superadmin` field for enhanced access control.
- Added unit tests for the new privileges functionality and guards to ensure correct behavior.

src/modules/auth/auth.module.ts

@@ -5,6 +5,8 @@ import { JwtModule } from '@nestjs/jwt';
 import { PassportModule } from '@nestjs/passport';
 import { ThrottlerGuard, ThrottlerModule } from '@nestjs/throttler';
 import { JwtAuthGuard } from '../../common/guards/jwt-auth.guard';
+import { PrivilegesGuard } from '../../common/guards/privileges.guard';
+import { PrivilegesModule } from '../privileges/privileges.module';
 import { UsersModule } from '../users/users.module';
 import { AuthController } from './auth.controller';
 import { AuthService } from './auth.service';
@@ -15,6 +17,7 @@ import { JwtStrategy } from './strategies/jwt.strategy';
 @Module({
   imports: [
     UsersModule,
+    PrivilegesModule,
     PassportModule.register({ defaultStrategy: 'jwt' }),
     JwtModule.registerAsync({
       imports: [ConfigModule],
@@ -36,7 +39,9 @@ import { JwtStrategy } from './strategies/jwt.strategy';
     RefreshTokensRepository,
     RevokedAccessTokensRepository,
     JwtStrategy,
+    // Registration order = execution order: JWT before privileges.
     { provide: APP_GUARD, useClass: JwtAuthGuard },
+    { provide: APP_GUARD, useClass: PrivilegesGuard },
     { provide: APP_GUARD, useClass: ThrottlerGuard },
   ],
   exports: [AuthService],