feat: Add Register DTOs and SP for public registration (Refs #2)

Backend/PruebaGentle.Core/DTOs/RegisterDto.cs

@@ -0,0 +1,22 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace PruebaGentle.Core.DTOs;
+
+public class RegisterDto
+{
+    [Required]
+    [StringLength(50, MinimumLength = 3)]
+    public string Username { get; set; } = string.Empty;
+
+    [Required]
+    [StringLength(100, MinimumLength = 6)]
+    public string Password { get; set; } = string.Empty;
+
+    [Required]
+    [EmailAddress]
+    public string Email { get; set; } = string.Empty;
+
+    [Required]
+    [StringLength(100)]
+    public string NombreCompleto { get; set; } = string.Empty;
+}

Backend/PruebaGentle.Core/DTOs/RegisterResponseDto.cs

@@ -0,0 +1,8 @@
+namespace PruebaGentle.Core.DTOs;
+
+public class RegisterResponseDto
+{
+    public string Token { get; set; } = string.Empty;
+    public DateTime ExpiresAt { get; set; }
+    public int UserId { get; set; }
+}