export function proxyImage(url: string | null | undefined): string | undefined {
    if (!url) return undefined;
    // Already a local path (e.g. cached media) — load it directly. The proxy
    // only knows how to handle Instagram's own CDN hosts, and a relative
    // path has no host at all, so it would otherwise get rejected.
    if (url.startsWith('/')) return url;
    return `/image-proxy?url=${encodeURIComponent(url)}`;
}