export declare function getOverlayPath(projectRoot: string): string;
export declare function writeOverlay(projectRoot: string, additions: Record<string, unknown>): void;
export declare function readOverlay(projectRoot: string): Record<string, unknown> | null;
/**
 * Merge overlay additions into .claude/settings.json.
 * Deep-merges objects, concatenates arrays (deduplicating strings).
 */
export declare function applyOverlay(projectRoot: string): void;
/**
 * Remove overlay additions from .claude/settings.json.
 * Strips keys/values that came from the overlay.
 */
export declare function stripOverlay(projectRoot: string): void;
