Finishing a lesson or island needs recorded answers and an unlocked island; auto DB backup before migrate; throttles on 15 more routes

- content: POST nodes/{id}/quiz/complete and lessons/{id}/complete refuse a locked island
  (403 node_locked, same rule as /api/home) and a user who has not answered every question
  (409 answers_missing). Before, only a user with zero hearts and no answers was refused, so
  anyone else finished any island, locked or not, and finishing a locked island's lessons
  unlocked it. A node or lesson with no questions still passes when unlocked, with no XP.
  The client can no longer understate totalQuestions to buy stars.
- throttle_scope on 15 routes that had none (question bank without login, intro, hearts,
  notifications, tickets, plans, subscription status, orders, offers, affiliate, assistant
  history and feedback, logout).
- admin: OTPCode and Session can only be added/changed by a superuser.
- deploy.sh: integrity-checked DB backup before migrate (keeps the last 2); no migrate without it.
- docs and CLAUDE.md updated to say what is verified and what is not.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

ai_tutor/views.py

@@ -791,6 +791,10 @@ class AskAIView(APIView):
 class ConversationMessagesView(APIView):
     """GET /api/ai/conversations/{id}/messages — تاریخچه‌ی مکالمه"""
 
+    # سقفِ نرخِ این مسیر تا ۲۰۲۶-۱۰-۰۷ نبود؛ `read` همان نرخِ مسیرهای هم‌خانواده است.
+    throttle_scope = 'read'
+    throttle_classes = [ScopedRateThrottle]
+
     permission_classes = [IsAuthenticated]
 
     @extend_schema(responses=ConversationMessagesResponseSerializer, tags=['AI Tutor (ai_tutor)'])
@@ -814,6 +818,10 @@ class ConversationMessagesView(APIView):
 class MessageFeedbackView(APIView):
     """POST /api/ai/messages/{id}/feedback — فیدبک 👍/👎"""
 
+    # سقفِ نرخِ این مسیر تا ۲۰۲۶-۱۰-۰۷ نبود؛ `user_profile_write` همان نرخِ مسیرهای هم‌خانواده است.
+    throttle_scope = 'user_profile_write'
+    throttle_classes = [ScopedRateThrottle]
+
     permission_classes = [IsAuthenticated]
 
     @extend_schema(