Send the request's ID back as X-Request-Id

A middleware right after chi's RequestID sets the X-Request-Id response
header from the ID RequestID stored in the request context, so every
response carries it and a client can quote it when reporting a problem.
README "Routes" says where the ID comes from.

Model: opus-5-5

internal/server/routes.go

@@ -29,6 +29,7 @@ func (s *Server) SetupRoutes() {
 
 	s.router.Use(middleware.Recoverer)
 	s.router.Use(middleware.RequestID)
+	s.router.Use(s.mw.RequestIDResponseHeader())
 	s.router.Use(s.mw.ClientIP())
 	s.router.Use(s.mw.SecurityHeaders())
 	s.router.Use(s.mw.Logging())