feat: initial commit — local services (backend + manager dashboard + waiter PWA)

Includes all work to date:
- local_backend: FastAPI backend with products, orders, tables, shifts, cloud sync
- manager_dashboard: React manager UI with product/category management, reports, settings
- waiter_pwa: React PWA for waiter devices
- Category reparent endpoint and UI
- Waiter domain: local_ip sent on heartbeat, waiter_domain persisted from cloud response
- QR code modal in AppInfoTab for waiter domain
- Product form: number input spinners removed, category pre-selected on new product
- Category row: count badge moved to far right

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

local_backend/schemas/settings.py

@@ -0,0 +1,16 @@
+from pydantic import BaseModel
+from typing import Optional
+from schemas.base import UTCDatetime
+
+
+class PosSettingOut(BaseModel):
+    key: str
+    value: str
+    updated_at: Optional[UTCDatetime] = None
+    updated_by_id: Optional[int] = None
+
+    model_config = {"from_attributes": True}
+
+
+class UpdateSettingRequest(BaseModel):
+    value: str