US08-01: Make the Trust Boundary Configurable and Authenticated

photo_pipeline/api/app.py

@@ -35,7 +35,13 @@ from photo_pipeline.api.routes import (
     uploads,
     workflow,
 )
-from photo_pipeline.api.security import DEFAULT_HEADERS, SecurityMiddleware, Session
+from photo_pipeline.api.security import (
+    DEFAULT_HEADERS,
+    FailureLimiter,
+    SecurityMiddleware,
+    Session,
+    trust_refusal,
+)
 
 # Registers the safety_score / analysis job handlers on import.
 import photo_pipeline.jobs.domain_handlers  # noqa: F401
@@ -84,9 +90,16 @@ def _install_error_handlers(app: FastAPI) -> None:
         return _envelope(500, "internal_error", "internal error")
 
 
+class ConfigurationRefused(RuntimeError):
+    """The configuration would serve the library to callers it cannot authenticate."""
+
+
 def create_app(config: Config | None = None) -> FastAPI:
     config = config or Config.from_env()
     configure_logging(config.log_level, config.log_format)
+    # Before anything is built, let alone bound to a port (US08-01).
+    if (why := trust_refusal(config)) is not None:
+        raise ConfigurationRefused(why)
 
     @asynccontextmanager
     async def lifespan(app: FastAPI):
@@ -114,6 +127,10 @@ def create_app(config: Config | None = None) -> FastAPI:
     # One session per process: the browser exchanges it for a cookie + CSRF token,
     # and every other origin is refused before a route ever runs (US07-02).
     app.state.session = Session.create()
+    app.state.access_limiter = FailureLimiter()
+    # Also set in the lifespan, but the bootstrap route reads it, and a caller can
+    # arrive before anything else has touched app.state.
+    app.state.config = config
     app.add_middleware(SecurityMiddleware, session=app.state.session, config=config)
     _install_error_handlers(app)
     app.include_router(session_routes.router, prefix="/api/v1")