add initial implementation of auth gateway with models, routes, and session management

containers/auth-gateway/auth_gateway/main.py

@@ -0,0 +1,37 @@
+from contextlib import asynccontextmanager
+from pathlib import Path
+
+from auth_gateway.config_loader import RuntimeConfigStore
+from auth_gateway.services.oidc_service import OIDCService
+from auth_gateway.services.session_service import SessionService
+from auth_gateway.settings import settings
+from auth_gateway.storage.sqlite import SQLiteStorage
+from auth_gateway.web.auth_routes import router as auth_router
+from auth_gateway.web.login_routes import router as login_router
+from fastapi import FastAPI
+from fastapi.staticfiles import StaticFiles
+from fastapi.templating import Jinja2Templates
+
+BASE_DIR = Path(__file__).resolve().parent
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    storage = SQLiteStorage(settings.database_path)
+    app.state.settings = settings
+    app.state.config_store = RuntimeConfigStore(settings.config_dir)
+    app.state.session_service = SessionService(storage, settings.session_default_minutes, settings.oidc_state_ttl_minutes)
+    app.state.oidc_service = OIDCService()
+    app.state.templates = Jinja2Templates(directory=str(BASE_DIR / "templates"))
+    yield
+
+
+app = FastAPI(title="Auth Gateway", lifespan=lifespan)
+app.mount("/static", StaticFiles(directory=str(BASE_DIR / "static")), name="static")
+app.include_router(auth_router)
+app.include_router(login_router)
+
+
+@app.get("/health")
+async def healthcheck():
+    return {"status": "ok"}