/**
 * Write this exact hook on disk and return its immutable path for NODE_OPTIONS.
 *
 * Providers of different package versions share ~/.termfleet. A global mutable filename lets an
 * older provider replace a newer pane's preload during its next window creation. Content-addressing
 * makes each pane keep the hook contract its own provider installed.
 */
export declare function ensurePortholeHook(): string;