Personal-data catalog spec, D1: a "Log files" card on Settings ›
Security › Hardening reads and sets inbuxa:LogSettings.keepForDays.
It says plainly what the files hold and whether they're kept with no
limit or deleted after N days on every server; Change… takes whole
days, at least one, and "Keep every file" goes back to no limit.
Visible with sysTracerGet, editable with sysTracerUpdate; on a server
without the setting the card isn't shown.
Tested: unit tests for reading the setting and the day rule;
typecheck, lint; in headless Chrome against a local server on
inbuxa-server feature/log-retention: no limit, then 21 days, then back.