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/routers/shifts.py

@@ -356,13 +356,15 @@ def get_shift_summary(
         OrderItem.status == "paid",
     ).all()
 
+    from datetime import timezone as tz
+    upper_bound = shift.ended_at or datetime.now(tz.utc)
     ordered_items = db.query(OrderItem).options(
         joinedload(OrderItem.product),
         joinedload(OrderItem.order),
     ).filter(
         OrderItem.added_by == waiter_id,
         OrderItem.added_at >= shift.started_at,
-        OrderItem.added_at <= shift.ended_at,
+        OrderItem.added_at <= upper_bound,
         (OrderItem.paid_in_shift_id != shift_id) | (OrderItem.paid_in_shift_id == None),
     ).all()