feat(local_backend): reservations, print analytics, workday summary, zone-PIN management

- New reservations module: model, schema, router (CRUD + status updates + upcoming alerts)
  and background task for auto-expiring stale reservations
- Reports: print_products, print_categories, print_tables analytics endpoints
  plus meta_products and business_day_summary for workday close/view flow
- printer_service: configurable font sizes/weights, donut/bar chart print layout helpers,
  analytics print blocks per printer
- tables/schemas: surfaced color, zone, and other new fields on Table, Product, User, Printer
- demo_seed.py for quick dev DB population; wipe_database.py utility

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

local_backend/Dockerfile

@@ -7,4 +7,4 @@ RUN pip install --no-cache-dir -r requirements.txt
 
 COPY . .
 
-CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000"]
+CMD ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000", "--log-level", "info"]