style: apply black and isort formatting

Run formatting tools on Phase 1 changes:
- black (code formatter)
- isort (import sorter)
- ruff (linter)

All linting checks pass.

backend/tests/test_products_pricing.py

@@ -1,10 +1,11 @@
 import uuid
 
+from sqlmodel import select
+
 from innercontext.api import products as products_api
 from innercontext.models import PricingRecalcJob, Product
 from innercontext.models.enums import DayTime, ProductCategory
 from innercontext.services.pricing_jobs import process_one_pending_pricing_job
-from sqlmodel import select
 
 
 def _product(