feat: completar fases 3 y 4 del roadmap mvp (gradebook, drag-and-drop, impersonacion) y actualizar README

backend/app/utils/jwt_decorators.py

@@ -40,6 +40,20 @@ def jwt_required(f):
             g.jwt_user = user
             g.jwt_payload = payload
             g.jwt_token = token
+            g.real_admin_user = user
+            g.is_impersonating = False
+
+            impersonate_header = request.headers.get('X-Impersonate-User')
+            if impersonate_header and user.is_admin():
+                target_user = None
+                if impersonate_header.strip().isdigit():
+                    target_user = db.session.get(User, int(impersonate_header.strip()))
+                else:
+                    target_user = User.query.filter_by(email=impersonate_header.strip()).first()
+
+                if target_user and target_user.is_active:
+                    g.jwt_user = target_user
+                    g.is_impersonating = True
 
         except jwt.ExpiredSignatureError:
             return jsonify({