Function housekeep 

pub async fn housekeep(
    cfg: &Config,
    home: &Path,
    worktrees_root: &Path,
    now: Timestamp,
) -> Housekeeping

Run the janitor: fold due runs, then prune the cache if it is over its cap.

Both halves are best-effort; a jammed cache lock or a run whose worktree another borrower holds must not stop the other half. Errors are reported through tracing::warn - this is housekeeping, and the daemon keeps serving either way.