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>

rag/tests_guardrails.py

@@ -138,3 +138,23 @@ class GuardrailThroughTheApiTests(TestCase):
         self.assertEqual(response.json()['answer'], guardrails.REFUSAL)
         self.assertEqual(response.json()['usedChunks'], [])
         self.assertEqual(Message.objects.get(role='assistant').text, guardrails.REFUSAL)
+
+
+class AgeToneTests(SimpleTestCase):
+    """لحن از سن، محتوا از پایه: بزرگسالی که سومِ دبستان برداشته لحنِ کودکانه نمی‌گیرد."""
+
+    def test_adult_in_a_primary_grade_gets_the_adult_tone_but_the_books_notation(self):
+        from .services.generation import _NUMBERS, _TONE
+
+        prompt = system_prompt('سوم', age=40)
+        self.assertIn(_TONE['adult'], prompt)
+        self.assertNotIn(_TONE['primary'], prompt)
+        self.assertIn(_NUMBERS['primary'], prompt)
+        self.assertIn('بزرگسال', prompt.split('\n')[0])
+
+    def test_child_or_unknown_age_keeps_the_grade_tone(self):
+        from .services.generation import _TONE
+
+        self.assertIn(_TONE['primary'], system_prompt('سوم', age=8))
+        self.assertIn(_TONE['primary'], system_prompt('سوم'))
+        self.assertIn(_TONE['upper'], system_prompt('دوازدهم', age=17))