rebuild(stage-2): establish runtime and persistence foundations

next/backend/http/request_context.py

@@ -0,0 +1,15 @@
+from __future__ import annotations
+
+import uuid
+
+from fastapi import FastAPI, Request
+
+
+def install_request_context(application: FastAPI) -> None:
+    @application.middleware("http")
+    async def request_context(request: Request, call_next):
+        request_id = uuid.uuid4().hex
+        request.state.request_id = request_id
+        response = await call_next(request)
+        response.headers["X-Request-ID"] = request_id
+        return response