senior's post-demo changes: parent report in the student's own account, Jalali birth date, invoices, math-only tutor, priced quotas

- remove the family app from the root (separate parent accounts, invite codes, parental
  settings); progress.0006 drops its tables, permissions and migration history, and
  Profile.parent_phone, the two family notification types and ?userId= on
  /api/progress/nodes go with it
- GET /api/user/weekly-report: last 7 days next to the 7 before (estimated minutes,
  questions, accuracy, islands, tutor questions) for the "parent report" page
- profile birthDate in Jalali (accounts/jalali.py), ages 5-99, birthYear derived from it
- GET /api/payment/invoices; orders now snapshot list price and plan title
- tutor answers only math: server pre-filter, scope rule in the prompt (tutor-v11),
  refusal marker replaced with fixed text; self-harm gets a help line instead
- streamed answers now record token usage (it was always 0)
- daily tutor quota: AI_DAILY_QUOTA_FREE (default 3) vs Plan.ai_daily_quota
- delete_users management command for wiping test accounts across every app
- docs/ai-cost-and-guardrails.md: measured cost per question and guardrail results

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

notifications/models.py

@@ -5,15 +5,13 @@ class Notification(models.Model):
     # انواع رویدادهایی که این اپ فقط بهشون گوش می‌ده (event-listener)؛
     # خودش تولیدکننده‌ی رویداد نیست. طبق سند معماری:
     # LessonCompleted/XPEarned (Progress), OrderPaid (Payment),
-    # TicketReplied (Support), FamilyLinkAccepted/WeeklyReportReady (Family)
+    # TicketReplied (Support).
     TYPE_CHOICES = [
         ('xp_earned', 'امتیاز گرفتی'),
         ('lesson_completed', 'درس تکمیل شد'),
         ('node_completed', 'جزیره تمام شد'),
         ('order_paid', 'پرداخت موفق'),
         ('ticket_replied', 'پاسخ تیکت'),
-        ('family_link_accepted', 'اتصال خانواده تأیید شد'),
-        ('weekly_report_ready', 'گزارش هفتگی آماده شد'),
     ]
 
     user_id = models.IntegerField(db_index=True)  # ارجاع سبک به accounts.User