Audit fixes 2026-10-03: seed keeps admin edits, plan cache, refresh limit, payment and tutor guards

- seed_content no longer undoes admin work: a SeedRecord ledger (content/seed_sync.py)
  stops deleted/renamed/re-worded content from being recreated and keeps admin-edited
  lesson text; new rows in the seed files still arrive (migration content.0010)
- plan list cache is invalidated on Plan save (receiver used a stale 'v1' key)
- token refresh per-IP cap 30/hour -> 600/hour (TOKEN_REFRESH_IP_RATE)
- a failed gateway result only changes a pending order (forged NOK no longer
  overwrites refunded/canceled)
- tutor gets the correct answer only after the student has answered
- support reply notification moved to a TicketMessage post_save signal
- global daily cap on paid AI questions (AI_GLOBAL_DAILY_MAX, default 3000)
- Bazaar verify uses only the order's SKU; bazaar orders require a SKU
- /api/health warns on the committed signing key; deploy.sh saves local commits;
  400 for bad ?unit= / ?period=; account delete keeps the referrer's Conversion
- earlier today: no stub answers outside DEBUG, ?grade= removed, logged fallbacks

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

subscription/receivers.py

@@ -4,8 +4,10 @@ from django.db.models.signals import post_delete, post_save
 from django.dispatch import receiver
 
 from .models import Plan
-
-PLANS_CACHE_KEY = 'subscription:plans:v1'  # هم‌تراز با subscription/views.py
+# کلید فقط یک‌جا تعریف می‌شود (views). تا ۲۰۲۶-۱۰-۰۳ این‌جا یک نسخه‌ی جدا ('v1') بود که
+# با v3 شدنِ کلیدِ views جا ماند: ذخیره‌ی پلن در ادمین کش را پاک نمی‌کرد و اپ تا یک ساعت
+# قیمتِ قدیم را نشان می‌داد در حالی که سفارش با قیمتِ تازه ساخته می‌شد (بازتولید شد).
+from .views import PLANS_CACHE_KEY
 
 
 @receiver(post_save, sender=Plan, dispatch_uid='subscription_invalidate_plans_cache_on_save')