/** Walk up from `cwd` until either a `.claude-switch` is found, a `.git/`
 *  boundary stops us, or we reach `os.homedir()` / fs root. Returns the
 *  absolute path of the first `.claude-switch` we hit (closest to cwd) or
 *  null. */
export declare function findClaudeSwitchFile(cwd: string, home?: string): string | null;