/**
 * Bound a log file by keeping at most one rotated generation. When `file`
 * exceeds `maxBytes`, the previous `.1` is discarded and the current file is
 * renamed to `.1`, so total on-disk cost is at most `2 * maxBytes`.
 *
 * A single subsystem must never be able to fill the disk with logs. Both the
 * structured logger and the gateway's inherited stdout/stderr files route
 * through here (SKY-105).
 *
 * Best-effort and synchronous: a rotation failure must never break logging or
 * gateway startup, so errors are swallowed. Returns whether a rotation happened.
 */
export declare function rotateLogIfLarge(file: string, maxBytes: number): boolean;