feat(auth): implement Google and Zalo OAuth backend strategies

Add complete OAuth2 authentication flow for Google and Zalo providers:
- OAuthService: handles account linking (by email/phone), new user
  creation for OAuth-only accounts, and JWT token generation
- GoogleOAuthStrategy: passport-google-oauth20 integration
- ZaloOAuthStrategy: custom OAuth2 implementation using Zalo's API
  (authorization URL generation, code exchange, user info fetch)
- OAuthController: redirect and callback endpoints for both providers
  with httpOnly cookie-based token management
- Unit tests for OAuthService (7 tests), GoogleOAuthStrategy (4 tests),
  and ZaloOAuthStrategy (7 tests)
- OAuth env vars added to .env.example and env-validation warnings

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/api/src/modules/auth/auth.module.ts

@@ -12,10 +12,14 @@ import { REFRESH_TOKEN_REPOSITORY } from './domain/repositories/refresh-token.re
 import { USER_REPOSITORY } from './domain/repositories/user.repository';
 import { PrismaRefreshTokenRepository } from './infrastructure/repositories/prisma-refresh-token.repository';
 import { PrismaUserRepository } from './infrastructure/repositories/prisma-user.repository';
+import { OAuthService } from './infrastructure/services/oauth.service';
 import { TokenService } from './infrastructure/services/token.service';
+import { GoogleOAuthStrategy } from './infrastructure/strategies/google-oauth.strategy';
 import { JwtStrategy } from './infrastructure/strategies/jwt.strategy';
 import { LocalStrategy } from './infrastructure/strategies/local.strategy';
+import { ZaloOAuthStrategy } from './infrastructure/strategies/zalo-oauth.strategy';
 import { AuthController } from './presentation/controllers/auth.controller';
+import { OAuthController } from './presentation/controllers/oauth.controller';
 
 const CommandHandlers = [
   RegisterUserHandler,
@@ -41,7 +45,7 @@ const QueryHandlers = [GetProfileHandler, GetAgentByUserIdHandler];
       signOptions: { expiresIn: '15m', audience: 'goodgo-api', issuer: 'goodgo-platform' },
     }),
   ],
-  controllers: [AuthController],
+  controllers: [AuthController, OAuthController],
   providers: [
     // Repositories
     { provide: USER_REPOSITORY, useClass: PrismaUserRepository },
@@ -50,14 +54,17 @@ const QueryHandlers = [GetProfileHandler, GetAgentByUserIdHandler];
     // Strategies
     JwtStrategy,
     LocalStrategy,
+    GoogleOAuthStrategy,
+    ZaloOAuthStrategy,
 
     // Services
     TokenService,
+    OAuthService,
 
     // CQRS
     ...CommandHandlers,
     ...QueryHandlers,
   ],
-  exports: [TokenService, USER_REPOSITORY],
+  exports: [TokenService, OAuthService, USER_REPOSITORY],
 })
 export class AuthModule {}