- Improved OAuth2 Tester UI/UX: added support for multiple HTTP methods, query parameters, request body validation, collapsible result sections, and dynamic input handling.
- Enhanced `UserController` with validation annotations for `UserDTO` in API requests.
- Updated `UserDTO` to include stricter validation constraints (`@NotNull`, `@NotBlank`, `@Email`).
- Adjusted CORS configuration to allow all origins for OAuth endpoints.
- Introduced `OAuth2 API Tester` (HTML+JS) in `/tools`.
- Updated security configuration:
- Added comprehensive CORS configurations for OAuth endpoints.
- Enhanced CSRF handling to exclude `/oauth2/token`.
- Adjusted role handling to ensure case-insensitivity.
- Fixed `RIGHT-MANAGEMENT` role in `UserController`.
- Replaced logo asset in frontend.
