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

app/routes/contacts.py

@@ -2,7 +2,6 @@
 
 from __future__ import annotations
 
-import asyncio
 import csv
 import io
 import uuid