Roll a Roblox project's place back to a previously-published version.
For a `roblox_game` project, re-publishes the RETAINED build artifact for
`version_number` (get published versions from the web Roblox Publishing card)
— it never rebuilds from source, so rollback is fast + deterministic. This
mints a NEW Roblox version pointing at the old build. Unknown version → 404;
a version with no retained artifact → 422; a place open in Studio /
rate-limited → 409 (retry); an invalid or unscoped Open Cloud key → 409 /
403. Returns {version_number, env, published_at, status, next_step}.
Connector