/**
 * Where user-facing browser caches (CloakBrowser binaries, CDP launcher
 * profiles, etc.) are allowed to live.
 *
 * Restricting the writable set to the user's home directory makes it safe to
 * expose `cacheDir` / `userDataDir` over the gateway HTTP API: an attacker who
 * already controls the gateway session cannot trick the install/launch flow
 * into seeding files under `/etc`, `/usr/local`, etc.
 *
 * Leading `~` and `~/` are expanded against the current process owner's home.
 */
export interface CacheDirCheckOk {
    ok: true;
    resolved: string;
}
export interface CacheDirCheckErr {
    ok: false;
    message: string;
    resolved: string;
}
export type CacheDirCheck = CacheDirCheckOk | CacheDirCheckErr;
export declare function expandHome(input: string): string;
/**
 * Returns `{ ok: true, resolved }` when `input` is an absolute (or `~`-rooted)
 * path that resolves inside the user's home directory. Empty / missing input
 * is allowed (callers fall back to their own default).
 */
export declare function checkCacheDir(input: string | undefined | null): CacheDirCheck;
/** Throws when the path violates the policy. */
export declare function assertCacheDir(input: string | undefined | null): string;