/**
 * Validates that file extension matches the declared MIME type with standardized error handling
 *
 * This function wraps validateMimeTypeAndExtensionMatch to provide consistent
 * error handling across the codebase. It prevents MIME type spoofing attacks
 * (CVE-2025-61687) by ensuring file extensions match declared MIME types.
 *
 * @param {string} filename The original filename
 * @param {string} mimetype The declared MIME type
 * @throws {InternalFlowiseError} If validation fails, throws BAD_REQUEST error
 * @example
 * ```typescript
 * validateFileMimeTypeAndExtensionMatch(file.originalname, file.mimetype)
 * ```
 */
export declare function validateFileMimeTypeAndExtensionMatch(filename: string, mimetype: string): void;
/**
 * Sanitizes the allowedUploadFileTypes string from chatbotConfig by keeping only
 * MIME types that are in the server allow list. Removes any type not in the list
 * (e.g. executables) to prevent malicious clients from persisting dangerous types.
 *
 * @param {string} allowedTypesString Comma-separated MIME types from config
 * @returns {string} Comma-separated string of allowed MIME types only
 */
export declare function sanitizeAllowedUploadMimeTypesFromConfig(allowedTypesString: string): string;