Initial KDS scaffold — Phase 2 kitchen port

FastAPI backend (Python 3.11, httpx for SignalR/GraphQL — no MSSQL ODBC),
shares kitchen_db directly. React/TS/Vite fullscreen board frontend.

Backend: auth.py (APP_SLUG=kds, SimpleNamespace), main.py (4 KDS migrations,
SignalR start/stop), kds.py router, models (kds/settings/resos — read from
kitchen_db), signalr_listener.py (backoff pre-existing), kds_graphql.py,
database.py. Requirements stripped to ~9 packages; image ~400 MB lighter
than kitchen (no MSSQL ODBC layer).

Frontend: AuthGate (app=kds), single fullscreen route, dark board theme.
KDS.tsx URL prefix patched (/api/kds/ → /kds/api/kds/),
recipe images cross-app (/kitchen/api/recipes/).
nginx: 5 blocks with SSE proxy headers on /kds/api/ block.

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

backend/main.py

@@ -0,0 +1,66 @@
+import logging
+from contextlib import asynccontextmanager
+
+from fastapi import FastAPI
+
+from database import engine, Base
+
+logging.basicConfig(
+    level=logging.INFO,
+    format='%(asctime)s - %(name)s - %(levelname)s - %(message)s'
+)
+
+from api import kds as kds_api
+
+from migrations.add_kds_tables import run_migration as run_kds_tables
+from migrations.add_kds_course_flow import run_migration as run_kds_course_flow
+from migrations.add_kds_order_tracking import run_migration as run_kds_order_tracking
+from migrations.add_kds_bookings_refresh import run_migration as run_kds_bookings_refresh
+
+from services.signalr_listener import start_signalr_listener, stop_signalr_listener
+
+logger = logging.getLogger(__name__)
+
+
+async def _run(name, coro):
+    try:
+        await coro()
+        logger.info(f"{name} migration completed")
+    except Exception as e:
+        logger.warning(f"{name} migration warning (may be expected): {e}")
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    # Create any SQLAlchemy-mapped KDS tables (idempotent)
+    async with engine.begin() as conn:
+        await conn.run_sync(Base.metadata.create_all)
+
+    # KDS migrations — extend kitchen_db schema with KDS columns/tables.
+    # Requires kitchen to be deployed first (kitchen_settings must exist).
+    await _run("KDS tables", run_kds_tables)
+    await _run("KDS course flow", run_kds_course_flow)
+    await _run("KDS order tracking", run_kds_order_tracking)
+    await _run("KDS bookings refresh", run_kds_bookings_refresh)
+
+    await start_signalr_listener()
+
+    yield
+
+    await stop_signalr_listener()
+    await engine.dispose()
+
+
+app = FastAPI(
+    title="KDS",
+    description="Kitchen Display System — SambaPOS SignalR ticket feed, course flow",
+    version="1.0.0",
+    lifespan=lifespan,
+)
+
+app.include_router(kds_api.router, prefix="/api/kds", tags=["KDS"])
+
+
+@app.get("/health")
+async def health_check():
+    return {"status": "healthy"}