/**
 * Returns a safe href for rich-text anchors, or null when the value should not be rendered.
 *
 * Policy:
 * - Allow absolute URLs with protocols: http, https, mailto, tel.
 * - Allow root-relative ("/path") and hash-only ("#section") links.
 * - Reject protocol-relative URLs ("//example.com"), bare domains ("example.com"),
 *   executable schemes (javascript/data/vbscript), malformed URLs, and empty values.
 * - Preserve percent-encoding from the original normalized input.
 */
export declare function sanitizeHref(raw: unknown): string | null;
