/**
 * JSON / NDJSON serialization utilities for CLI output.
 *
 * - stableStringify: pretty-printed, sorted-key JSON (--json)
 * - compactStringify: single-line, sorted-key JSON (--ndjson)
 * - sanitizePayload: strips internal _-prefixed keys before serialization
 */
/**
 * Pretty-printed JSON with sorted keys (2-space indent).
 */
export declare function stableStringify(value: unknown): string;
/**
 * Single-line JSON with sorted keys (no indent).
 */
export declare function compactStringify(value: unknown): string;
/**
 * Shallow-clones a payload, removing all top-level underscore-prefixed keys.
 * These are internal rendering artifacts (e.g. _renderedSvg, _renderedAscii)
 * that should not leak into JSON/NDJSON output.
 */
export declare function sanitizePayload(payload: unknown): unknown;
