/**
 * YAML load/save helpers with deterministic serialization and schema validation.
 *
 * - `loadYaml<T>()` loads and optionally validates a YAML file.
 * - `saveYaml()` serializes data deterministically (stable key order, block style)
 *   so that single-field changes produce minimal git diffs (≤ 3 lines).
 *
 * Requirements: 4.2 (minimal diffs), 4.7 (validation errors name the file).
 */
/**
 * A lightweight schema validator function.
 * Returns null/undefined when valid, or an error message string on failure.
 */
export type SchemaValidator<T = unknown> = (data: unknown) => string | null | undefined;
/**
 * Error thrown when YAML loading or validation fails.
 * Always includes the file path and a description of the failure.
 */
export declare class YamlLoadError extends Error {
    readonly filePath: string;
    readonly reason: string;
    constructor(filePath: string, reason: string);
}
/**
 * Load a YAML file, parse it, and optionally validate the result.
 *
 * @param filePath - Absolute or relative path to the YAML file.
 * @param validate - Optional validator; receives parsed data, returns error string on failure.
 * @returns The parsed (and validated) data cast to `T`.
 * @throws {YamlLoadError} If the file is missing, unparseable, or fails validation.
 */
export declare function loadYaml<T = unknown>(filePath: string, validate?: SchemaValidator<T>): T;
/**
 * Serialize `data` to YAML with deterministic output and write it to `filePath`.
 *
 * Deterministic properties:
 * - Stable key order (sorted alphabetically).
 * - Block style for readability.
 * - No line wrapping — one scalar per line.
 * - Repeated calls with the same data produce byte-identical output.
 *
 * Creates parent directories if they don't exist.
 *
 * @param filePath - Absolute or relative path for the output file.
 * @param data - The data to serialize.
 */
export declare function saveYaml(filePath: string, data: unknown): void;
/**
 * Serialize data to a YAML string with deterministic formatting.
 * Exported for testing without filesystem side effects.
 */
export declare function serializeYaml(data: unknown): string;
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