Add improvements 2

gateway/app/middleware/request_id.py

@@ -9,6 +9,8 @@ from fastapi import Request
 from starlette.middleware.base import BaseHTTPMiddleware
 from starlette.responses import Response
 
+from app.core.header_manager import header_manager
+
 logger = structlog.get_logger()
 
 
@@ -40,11 +42,9 @@ class RequestIDMiddleware(BaseHTTPMiddleware):
         # Bind request ID to structured logger context
         logger_ctx = logger.bind(request_id=request_id)
 
-        # Inject request ID header for downstream services
-        # This is done by modifying the headers that will be forwarded
-        request.headers.__dict__["_list"].append((
-            b"x-request-id", request_id.encode()
-        ))
+        # Inject request ID header for downstream services using HeaderManager
+        # Note: This runs early in middleware chain, so we use add_header_for_middleware
+        header_manager.add_header_for_middleware(request, "x-request-id", request_id)
 
         # Log request start
         logger_ctx.info(