🎨 style: порядок импортов по конфигу репозитория

Ruff в CI читает pyproject.toml из корня и сортирует импорты; локальный прогон
из каталога backend этого правила не видел.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

apps/backend/chatballs/calls/tests/test_flow.py

@@ -9,6 +9,7 @@ from urllib.parse import parse_qs, urlparse
 from django.utils import timezone
 
 from chatballs.calls.event_handlers import CallInviteDeliveryError, handle_call_invite_send
+from chatballs.calls.lifecycle import transition_call
 from chatballs.calls.models import (
     CallEndedBy,
     CallInvite,
@@ -16,7 +17,6 @@ from chatballs.calls.models import (
     CallStatus,
     InviteDeliveryStatus,
 )
-from chatballs.calls.lifecycle import transition_call
 from chatballs.calls.services import (
     decline_call_for_identity,
     open_call_for_identity,

apps/backend/chatballs/conversations/clients.py

@@ -18,6 +18,7 @@ from django.db.models import (
 )
 from django.db.models.functions import Coalesce
 
+from chatballs.conversations.contact_avatars import contact_avatar_url_in
 from chatballs.conversations.models import (
     ConnectionIdentity,
     Contact,
@@ -26,7 +27,6 @@ from chatballs.conversations.models import (
     Conversation,
     LifecycleState,
 )
-from chatballs.conversations.contact_avatars import contact_avatar_url_in
 from chatballs.i18n import t
 from chatballs.identity.audit_catalog import (
     audit_action_label,

apps/backend/chatballs/conversations/serializers.py

@@ -1,5 +1,6 @@
 from django.db.models import Count, Max, Q
 
+from chatballs.conversations.contact_avatars import contact_avatar_url_in
 from chatballs.conversations.models import (
     ConnectionIdentity,
     Conversation,
@@ -8,7 +9,6 @@ from chatballs.conversations.models import (
     MessageKind,
 )
 from chatballs.i18n import t
-from chatballs.conversations.contact_avatars import contact_avatar_url_in
 from chatballs.identity.avatars import user_avatar_url_in
 from chatballs.integrations.features import features_payload
 from chatballs.integrations.models import IntegrationProvider