feat: Add authentication DTOs and setup API routes for user and activity management

backend/internal/dtos/auth_dto.go

@@ -1,6 +1,13 @@
 package dto
 
-type AuthDto struct {
+// LoginDto represents the login request
+type LoginDto struct {
 	Email    string `json:"email"`
 	Password string `json:"password"`
 }
+
+// TokenDto represents the response after successful authentication
+type TokenDto struct {
+	Token string  `json:"token"`
+	User  UserDto `json:"user"`
+}