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/schemas/table.py

@@ -1,5 +1,6 @@
 from pydantic import BaseModel, field_validator
 from typing import Optional, List
+from datetime import datetime
 
 MAX_TABLE_NAME_LENGTH = 6
 
@@ -73,6 +74,16 @@ class TableFloorplanUpdate(BaseModel):
     floor_y: float
 
 
+class UpcomingReservation(BaseModel):
+    id: int
+    guest_name: str
+    party_size: int
+    reserved_for: datetime
+    status: str
+
+    model_config = {"from_attributes": True}
+
+
 class TableOut(BaseModel):
     id: int
     number: int
@@ -83,5 +94,6 @@ class TableOut(BaseModel):
     floor_y: Optional[float] = None
     group: Optional[TableGroupOut] = None
     has_active_order: bool = False
+    upcoming_reservation: Optional[UpcomingReservation] = None
 
     model_config = {"from_attributes": True}