- Create AvailabilityService with get_availability_for_range(), set_availability_for_date(), and copy_availability()
- Move slot validation logic to service
- Update routes/availability.py to use AvailabilityService
- Remove all direct database queries from routes
- Create PriceService with get_recent_prices() and fetch_and_store_price()
- Update routes/audit.py to use PriceService instead of direct queries
- Use PriceHistoryMapper consistently
- Update test to patch services.price.fetch_btc_eur_price