/**
 * Converts an HTML string to the markdown subset supported by markdownFormatter.
 *
 * Supported tags: strong, b, em, i, code, mark, s, strike, del, h1, h2, h3,
 * ul, ol, li, br, p.
 * The u and span tags, along with text-align styling on p/h1-h3, are rendered
 * as plain text: their styling is ignored but their content is preserved.
 * Other unsupported tags and their content are dropped entirely.
 * HTML entities are decoded to plain text.
 *
 * @param value - The HTML string to convert
 * @returns The equivalent markdown string, or empty string for null/undefined/empty input
 */
export declare function htmlToMarkdown(value?: string | null): string;
