Question packs removed at the root; all subscriptions 4 assistant questions a day; Bazaar is subscription-only

- subscription.0017/0018, payment.0013: pack plans deleted, QuestionCredit/HeartsPass models and Plan.kind /
  question_credits / hearts_days / Order.question_credits / hearts_days dropped. The only paid pack order was the
  company owner's test account (user 26).
- Assistant: no credit spending; quota is the daily cap only (free 2, every plan 4, gift subscription 4).
- Bazaar: verify_purchase is subscription-only (no inapp guess), start/purchase responses lose productType,
  verify refuses an order without a subscription. A paid order with no subscription now logs ERROR.
- Removed POST /api/payment/orders (internal; no caller). Its permission tests stay.
- Pack-based tests rewritten on subscriptions (refund, security, Bazaar token); pack-only test files deleted.
- docs: profit table for 4/day on both payment routes plus free users; handbook, operations, CLAUDE.md current.
949 tests green.

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

content/tests_paywall.py

@@ -62,9 +62,9 @@ class PaywallTests(TestCase):
 
     def test_status_reports_plan_title_and_quota(self):
         from subscription.models import Plan
-        plan = Plan.objects.get(kind='subscription', on_sale=True, duration_days=90)
+        plan = Plan.objects.get(on_sale=True, duration_days=90)
         Subscription.objects.create(user_id=self.user.id, plan=plan, status='active',
                                     expires_at=timezone.now() + timezone.timedelta(days=10))
         body = self.client.get('/api/subscription/status').json()
         self.assertEqual((body['active'], body['planTitle'], body['planDurationDays'], body['aiDailyQuota']),
-                         (True, 'سه‌ماهه', 90, 3))
+                         (True, 'سه‌ماهه', 90, 4))