chore: ruff lint auto-fix — 9 errors fixed (import sorting, unused imports)

- I001: import block sorting in main.py, routes/__init__.py, companies.py, conftest.py, check_indexes.py
- F401: unused imports removed (asyncio, UTC, datetime, AsyncSession)
- 6 ASYNC240/230 warnings remain (os.path.exists in async, open() in test) — minor, non-blocking

tests/conftest.py

@@ -50,6 +50,7 @@ from app.plugins.builtins.calendar.models import (  # noqa: F401
 from app.plugins.builtins.dms import DmsPlugin  # noqa: F401
 from app.plugins.builtins.dms.models import File as DmsFile  # noqa: F401
 from app.plugins.builtins.dms.models import Folder  # noqa: F401
+from app.plugins.builtins.entity_links.models import EntityLink  # noqa: F401
 from app.plugins.builtins.mail import MailPlugin  # noqa: F401
 from app.plugins.builtins.mail.models import (  # noqa: F401
     ContactPgpKey,
@@ -67,7 +68,6 @@ from app.plugins.builtins.mail.models import (  # noqa: F401
     PgpKey,
     VacationSentLog,
 )
-from app.plugins.builtins.entity_links.models import EntityLink  # noqa: F401
 from app.plugins.builtins.permissions import PermissionsPlugin  # noqa: F401
 from app.plugins.builtins.permissions.models import Permission, ShareLink  # noqa: F401
 from app.plugins.builtins.tags.models import Tag, TagAssignment  # noqa: F401