Turn prompt and response logging on or off, and choose how long it is kept

Account-wide. enabled: false stops storing content and deletes what is stored; we keep metadata only, so GET /client/requests/{id} has nothing to return for those calls. retention is how long stored content is kept: 7d, 30d (the default) or forever (until you delete it or turn logging off). A new retention applies to what is already stored, so a shorter one deletes older content at once. Requires projects:write.