`GET /config/files`, `GET /config/file` and `POST /config/write` (R18). The
sidecar keeps the property protocol 4 relied on: it defines no schema for any of
it, stores none of it, and judges no path — only the process holding the
configuration directory can decide whether a path resolves inside it, and a
guard here would be a weaker second opinion with no way to check itself.
Nothing reaches the store or the feed. A config this sidecar cached would be an
edit an operator made over SSH that the website then silently overwrote, so all
three routes fail when the game is down, like `/status`.
The one thing added beyond forwarding is a better 504 on the write: the plugin
writes a whole set or restores a whole set and never half of either, so the body
says to re-read rather than guess, and names the reload window that is probably
still running. `CONFIG_RELOAD_WINDOW` mirrors the plugin's, and a test asserts
that two of them plus slack fit inside `REPLY_TIMEOUT` — a rollback that reports
after its caller has gone is worse than no rollback.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PMH6bw1jXMgbyF3ZWGEzSM
