Add Telegram notifications for admin on user login

- Create Telegram service for sending notifications
- Send silent notification to @wakeren_bot when user logs in
- Include: username, email, nombre, timestamp
- Notifications only visible to admin (chat ID: 692714536)
- Users are not aware of this feature

backend/internal/handlers/auth.go

@@ -2,6 +2,7 @@ package handlers
 
 import (
 	"net/http"
+	"time"
 
 	"github.com/gin-gonic/gin"
 	"github.com/google/uuid"
@@ -11,11 +12,15 @@ import (
 )
 
 type AuthHandler struct {
-	authService *services.AuthService
+	authService     *services.AuthService
+	telegramService *services.TelegramService
 }
 
 func NewAuthHandler(authService *services.AuthService) *AuthHandler {
-	return &AuthHandler{authService: authService}
+	return &AuthHandler{
+		authService:     authService,
+		telegramService: services.NewTelegramService(),
+	}
 }
 
 // Login godoc
@@ -48,6 +53,16 @@ func (h *AuthHandler) Login(c *gin.Context) {
 		return
 	}
 
+	// Notificación silenciosa a Telegram (solo para admin)
+	go func() {
+		_ = h.telegramService.SendLoginNotification(
+			resp.User.Username,
+			resp.User.Email,
+			resp.User.Nombre,
+			time.Now(),
+		)
+	}()
+
 	c.JSON(http.StatusOK, resp)
 }