feat: Add RegisterAsync endpoint to AuthController (Refs #2)

Backend/PruebaGentle.API/Controllers/AuthController.cs

@@ -48,6 +48,40 @@ public class AuthController : ControllerBase
         });
     }
 
+    [HttpPost("register")]
+    public async Task<IActionResult> Register([FromBody] RegisterDto dto)
+    {
+        var user = new PruebaGentle.Core.Entities.User
+        {
+            Username = dto.Username,
+            PasswordHash = _passwordHasher.Hash(dto.Password),
+            Email = dto.Email,
+            NombreCompleto = dto.NombreCompleto
+        };
+
+        try
+        {
+            var created = await _userRepository.RegisterAsync(user);
+            var expiresAt = DateTime.UtcNow.AddHours(_jwtSettings.ExpirationHours);
+            var token = GenerateJwtToken(created.Id, created.Username, created.Email, expiresAt);
+
+            return Created(string.Empty, new RegisterResponseDto
+            {
+                Token = token,
+                ExpiresAt = expiresAt,
+                UserId = created.Id
+            });
+        }
+        catch (Microsoft.Data.SqlClient.SqlException ex) when (ex.Number == 50001)
+        {
+            return Conflict(new { error = "El nombre de usuario ya existe." });
+        }
+        catch (Microsoft.Data.SqlClient.SqlException ex) when (ex.Number == 50002)
+        {
+            return Conflict(new { error = "El email ya existe." });
+        }
+    }
+
     private string GenerateJwtToken(int userId, string username, string email, DateTime expiresAt)
     {
         var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_jwtSettings.Secret));