feat: add Nailong Fund advisor capabilities

app/api/middleware.py

@@ -0,0 +1,20 @@
+"""HTTP cross-cutting concerns."""
+
+from collections.abc import Awaitable, Callable
+
+from starlette.requests import Request
+from starlette.responses import Response
+
+TRACE_ID_HEADER = "X-Trace-ID"
+RequestHandler = Callable[[Request], Awaitable[Response]]
+
+
+async def attach_trace_id(request: Request, call_next: RequestHandler) -> Response:
+    """Return the request trace identifier on both success and error responses."""
+    response = await call_next(request)
+    context = getattr(request.state, "request_context", None)
+    trace_id = getattr(context, "trace_id", None) or getattr(request.state, "trace_id", None)
+    trace_id = trace_id or request.headers.get(TRACE_ID_HEADER)
+    if trace_id:
+        response.headers[TRACE_ID_HEADER] = str(trace_id)
+    return response