Remove the guest system entirely: no is_guest/device_id, no guest throttles, phone login is the only way in

accounts.0008 drops the columns and refuses to run while guest rows exist.
Docs describe the current state; tests that only proved guest behaviour are gone.

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

accounts/tests_delete_account.py

@@ -22,7 +22,7 @@ def _client(user):
 class DeleteAccountTests(TestCase):
     def setUp(self):
         cache.clear()
-        self.user = User.objects.create(phone='09121115001', is_guest=False)
+        self.user = User.objects.create(phone='09121115001')
         UserStats.objects.create(user_id=self.user.id, xp=50)
         self.client = _client(self.user)
 
@@ -53,12 +53,6 @@ class DeleteAccountTests(TestCase):
         # توکنِ قبلی دیگر به هیچ کاربری نمی‌رسد.
         self.assertIn(self.client.get('/api/user/profile').status_code, (401, 403))
 
-    def test_guest_confirms_by_typing_the_word(self):
-        guest = User.objects.create(device_id='guest-del', is_guest=True)
-        client = _client(guest)
-        self.assertEqual(client.post('/api/user/delete', {'confirm': 'باشه'}, format='json').status_code, 400)
-        self.assertEqual(client.post('/api/user/delete', {'confirm': 'حذف'}, format='json').status_code, 200)
-        self.assertFalse(User.objects.filter(pk=guest.pk).exists())
 
     @override_settings(TEST_LOGIN_PHONES={'09121115001': '4321'})
     def test_demo_accounts_cannot_be_deleted(self):