RSync URL for instrument server setup

I suspect that the instrument server doesn't pick up the `rsync_url` from the machine config

Start by tracing the instrument server setup and how it reads the machine configuration, focusing on whether rsync_url is loaded and applied. Confirm the behavior with the relevant existing checks or a focused reproduction; done means the server uses the configured rsync_url.

索引モデルが issue の本文から書いたものです。