import type { PreLaunchTrust } from './fsm-types.js';
/**
 * Idempotently add `workingDir` (realpath) to the trusted-folders array named
 * by `trust.key` inside the JSON settings file at `trust.settings_path`.
 *
 * - Creates the file (and parent dir) if missing.
 * - Preserves all other settings; only the trust array is touched.
 * - No-ops if the path is already present.
 * - Best-effort: any failure is logged and swallowed. A failed pre-trust must
 *   not block the launch — the worst case is the old behavior (the FSM still
 *   detects the trust modal as an approval state), not a crash.
 *
 * Returns the path that was added (realpath), or null if nothing changed /
 * an error occurred — purely so callers/tests can assert the effect.
 */
export declare function applyPreLaunchTrust(trust: PreLaunchTrust, workingDir: string): string | null;
