Security review fixes: admin permissions, guest sessions, payment edge cases, assistant leaks

- Admin: refund/cancel/mark-resolved/Bazaar-link actions need change permission; question and
  curriculum import need add/delete; content browser needs view_question; guest device ids are
  shown to superusers only.
- Accounts: registering a guest's phone revokes the guest's earlier sessions; self-deletion keeps
  Redemption, UserOffer and the phone's OTP rows; the public demo guest cannot be deleted
  (DEMO_GUEST_DEVICE_IDS); display-name contact filter covers any separator and social handles.
- Payment: callback without Authority is 400; a second Bazaar purchase on a paid order is 409;
  orders snapshot credits/hearts/days at creation (payment.0011).
- Assistant: a broken diagram no longer makes a streamed answer free; a late off-topic marker
  refuses the answer (not stored, not cached); a disconnect saves the partial answer; only
  KNOWN_COLLECTIONS are searched.
- Infra: secret-key file is created atomically (workers no longer split keys); no default
  INTERNAL_SERVICE_KEY; Kavenegar key and Bazaar token kept out of error logs; Swagger/ReDoc
  pinned; schema throttled; docker compose bound to 127.0.0.1; non-ASCII digit ids are 400;
  ticket text capped at 5000.
- docs/security-before-production.md: remaining open items 24-31 and the guard tests.

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

accounts/services.py

@@ -134,8 +134,10 @@ def _kavenegar_post(*, phone: str, method: str, payload: dict) -> None:
             'phone_suffix=%s method=%s', _phone_suffix(phone), method,
         )
         raise SMSDeliveryUncertain('پاسخِ سرویسِ پیامک دیر رسید.')
-    except requests.RequestException:
-        logger.exception('SMS request to provider failed: phone_suffix=%s', _phone_suffix(phone))
+    except requests.RequestException as exc:
+        # فقط نوعِ خطا: متنِ خطای requests آدرسِ کامل را دارد و کلیدِ API بخشی از همان آدرس است.
+        logger.error('SMS request to provider failed: phone_suffix=%s method=%s error=%s',
+                     _phone_suffix(phone), method, type(exc).__name__)
         raise SMSDeliveryError('ارسال پیامک با خطا مواجه شد.')
 
     if response.status_code != 200: