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

scripts/seed_perf_data.py

@@ -15,13 +15,12 @@ import asyncio
 import os
 import sys
 import uuid
-from datetime import UTC, datetime
 
 # Add project root to path
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
 from sqlalchemy import select
-from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
+from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine
 
 from app.config import get_settings
 from app.models.contact import Contact