/**
 * Validate that a requested path stays within the allowed root directory.
 * Prevents path traversal attacks (e.g., ../../etc/passwd).
 *
 * @param requestedPath - The path to validate (can be relative, or start with `~`)
 * @param allowedRoot - The root directory the path must stay within
 * @returns The resolved absolute path
 * @throws Error if path escapes the allowed root
 */
export declare function validatePath(requestedPath: string, allowedRoot: string): string;