Setup project correctly for development and release

src/remoteimage.ts

@@ -1,9 +1,7 @@
-import { fetch } from 'undici';     // Node ≥18 has global fetch; otherwise add undici
-
 export async function fetchAndEncode(url: string) {
   const res = await fetch(url);
   if (!res.ok) throw new Error(`Failed to fetch image: ${url}`);
   const buf = Buffer.from(await res.arrayBuffer());
-  const mimeType = res.headers.get('content-type') || 'image/png';
+  const mimeType = res.headers.get('content-type') ?? 'image/png';
   return { mimeType, data: buf.toString('base64') };
 }