/**
 * 7-day log rotation for peaks-loop.
 *
 * daily files are named by UTC date, so a "new day" automatically
 * means a new file. The retention sweep runs at the start of every
 * peaks-loop invocation and removes any `peaks-loop-*.log` whose
 * UTC date is more than `retentionDays` days behind today.
 *
 * No external dep — `fs.readdirSync` + `statSync.mtimeMs` (or, for
 * the name-derived path, parse the YYYY-MM-DD from the file name).
 * We prefer the file NAME (not mtime) so a user who copies an old
 * log back into the directory does not have it re-deleted on the
 * next sweep.
 */
export type ApplyRetentionOptions = {
    /** Number of days to keep. Defaults to 7. */
    retentionDays?: number;
    /** Wall-clock for tests. Defaults to `Date.now()`. */
    nowMs?: number;
    /** Override log dir (used by tests). */
    dirOverride?: string;
};
/**
 * Delete any `peaks-loop-YYYY-MM-DD.log` file in the log dir whose
 * UTC date is more than `retentionDays` days older than today.
 * Returns the absolute paths of the deleted files (for tests +
 * observability).
 *
 * The function is best-effort: a per-file unlink failure is
 * silently swallowed (the file may have been removed by another
 * process between the `readdir` and the `unlink`).
 */
export declare function applyRetention(opts?: ApplyRetentionOptions): string[];