feat: Refactor UserController to use UserMapper for DTO conversions

feat: Add ApiErrorDto and ApiValidationErrorDto for standardized error responses

feat: Implement ChangeAvatarRequest, ChangePasswordRequest, ChangeRoleRequest, ChangeStatusRequest, LoginRequest, LoginResponse, and RegisterRequest DTOs

feat: Create custom exceptions for better error handling: BadRequestException, ConflictException, ForbiddenException, NotFoundException, UnauthorizedException, and ValidationException

feat: Add RequestLoggingFilter for logging incoming requests

feat: Implement DevCorsConfig for CORS settings in development environment

feat: Create GlobalExceptionHandler for centralized exception handling

feat: Implement RestAccessDeniedHandler and RestAuthEntryPoint for handling access denied and unauthorized requests

feat: Create CustomPrincipal for Spring Security user details

feat: Implement JwtFilter and JwtService for JWT authentication

feat: Add PasswordGenerator for secure password generation

feat: Implement ServiceAuthFilter for service-level authentication

feat: Create AuthService for handling authentication and password changes

refactor: Update CustomUserDetailsService to use CustomPrincipal

refactor: Update UserService to improve user management and exception handling

fix: Update frontend API base URL in development and production settings

refactor: Clean up Header component and associated CSS

frontend/public/config/settings.prod.json

@@ -1,6 +1,6 @@
 {
   "apiConfig": {
-    "baseUrl": "http://localhost:3000",
+    "baseUrl": "https://adeptusminiaturium.es/api",
     "endpoints": {
       "auth": {
         "login": "/auth/login",