Make rekey not private and in integration api

server/lib/backupFileName.ts

@@ -1,14 +1,3 @@
-/**
- * Builds the timestamp segment of a database backup file name.
- *
- * `Date#getMonth` is zero-indexed, so building this inline produced names like
- * `db_2026-8-12_...` for a backup taken on 12 September 2026. Every field is
- * also zero-padded, which keeps the names unambiguous and makes them sort
- * lexicographically in the order they were taken.
- *
- * @param date The moment the backup is being taken. Defaults to now.
- * @returns A timestamp of the form `YYYY-MM-DD_HH-MM-SS`.
- */
 export function formatBackupTimestamp(date: Date = new Date()): string {
     const pad = (value: number): string => String(value).padStart(2, "0");