/**
 * Extracts a numbered code snippet around a 1-indexed vulnerable line.
 *
 * The returned snippet spans the range `[line-6, line+5]` in 0-indexed
 * coordinates, with the vulnerable line marked by `→` and all other lines
 * marked by two spaces. Returns `null` for unreadable/missing files,
 * oversized files (>2MB), known generated/minified paths, binary files,
 * or out-of-range line numbers.
 */
export declare function extractSnippet(filePath: string, line: number): string | null;