- Add Result<T> generic response template for standardized API output
- Introduce UserLoginDTO with validation annotations for login requests
- Migrate AuthController to use DTO binding and return Result responses
- Update AuthService interface to accept UserLoginDTO and return Boolean
- Add Jackson configuration (snake_case, non-null, date format)
- Include jackson-module-kotlin and spring-boot-starter-validation deps
- Register Argon2PasswordEncoder as a Spring bean
- Implement InitUserRunner to seed default users on startup
- Add spring-security-crypto and bouncycastle dependencies
- Include database schema initialization script