public user IDs, plans priced by tutor cost, age-based tutor tone, self-service account deletion

- profile publicId ("User482917", accounts/public_id.py); admin shows and searches it
- plans API reports aiDailyQuota per plan and freeAiDailyQuota; migration 0007 sets the
  temporary prices (monthly 99,000 / yearly 990,000 toman, 5 tutor questions a day) unless
  an admin already edited the yearly plan
- tutor tone follows the learner's age (18+ gets an adult tone at any grade); notation
  still follows the grade's book; answer cache keyed by tone (prompt tutor-v12-age-tone)
- POST /api/user/delete: phone users confirm with a fresh SMS code (same checks as login,
  now shared in verify_phone_otp), guests type "حذف"; payment records are kept, demo
  accounts refused
- delete_users --skip-paid

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

accounts/admin.py

@@ -51,8 +51,23 @@ class SendSMSForm(forms.Form):
 
 @admin.register(User)
 class UserAdmin(admin.ModelAdmin):
-    list_display = ('id', 'name', 'phone', 'device_id', 'is_guest', 'grade_id', 'created_at')
+    list_display = ('id', 'public_id', 'name', 'phone', 'device_id', 'is_guest', 'grade_id', 'created_at')
     search_fields = ('name', 'phone', 'device_id')
+
+    @admin.display(description='شناسه‌ی نمایشی')
+    def public_id(self, obj):
+        from .public_id import encode
+        return encode(obj.pk)
+
+    def get_search_results(self, request, queryset, search_term):
+        """«User482917» (همان که کاربر در پروفایلش می‌بیند) هم کاربر را پیدا می‌کند."""
+        from .public_id import decode
+
+        results, may_have_duplicates = super().get_search_results(request, queryset, search_term)
+        user_id = decode(search_term)
+        if user_id:
+            results |= queryset.filter(pk=user_id)
+        return results, may_have_duplicates
     list_filter = ('is_guest',)
     actions = ['send_sms_to_selected']