perf(AuthController): devolver JSON en mensajes de error

src/main/java/com/example/apprecetas/user/infrastructure/controller/AuthController.java

@@ -23,6 +23,7 @@ import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RestController;
 
 import java.net.URI;
+import java.util.Collections;
 import java.util.stream.Collectors;
 
 @RestController
@@ -51,13 +52,15 @@ public class AuthController {
             User user = readUserService.readByEmail(loginRequest.getEmail());
 
             if (!passwordEncoder.matches(loginRequest.getPassword(), user.getPassword()))
-                return ResponseEntity.status(HttpStatus.UNAUTHORIZED).body("Contraseña incorrecta");
+                return ResponseEntity.status(HttpStatus.UNAUTHORIZED)
+                        .body(Collections.singletonMap("message", "Contraseña incorrecta"));
 
             String token = jwtTokenProvider.generateToken(user.getId());
             return ResponseEntity.ok(new AuthResponse(token));
 
         } catch (EntityNotFoundException e) {
-            return ResponseEntity.status(HttpStatus.UNAUTHORIZED).body("Usuario no encontrado");
+            return ResponseEntity.status(HttpStatus.UNAUTHORIZED).
+                    body(Collections.singletonMap("message", "Usuario no encontrado"));
         }
     }