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>

progress/tests.py

@@ -23,7 +23,7 @@ class UserHeartsRegenTests(TestCase):
 
     def setUp(self):
         self.client = APIClient()
-        self.user = User.objects.create(device_id='dev-hearts-regen', is_guest=True, name='')
+        self.user = User.objects.create(phone='09000000001', name='')
         self.token = issue_access_token(self.user.id)
 
     def _get_hearts(self):
@@ -75,7 +75,7 @@ class CharacterGamificationTests(TestCase):
 
     def setUp(self):
         self.client = APIClient()
-        self.user = User.objects.create(device_id='device-characters-1', is_guest=True, name='')
+        self.user = User.objects.create(phone='09000000002', name='')
         self.token = issue_access_token(self.user.id)
 
         self.owl = Character.objects.create(slug='owl', name='جغد', icon='owl', unlock_xp=0, order=1)
@@ -275,7 +275,7 @@ class LeaderboardPeriodValidationTests(TestCase):
         from rest_framework.test import APIClient
 
         self.client = APIClient()
-        user = User.objects.create(device_id='lb-dev', is_guest=True)
+        user = User.objects.create(phone='09000000003')
         self.client.credentials(HTTP_AUTHORIZATION=f'Bearer {issue_access_token(user.id)}')
 
     def test_unknown_period_is_a_400(self):