feat: add links to entire article header

lib/cache/image.ts

@@ -178,6 +178,6 @@ export async function setImage(
         ? { suffix: opts.suffix }
         : { width: opts.width, height: opts.height }),
     }),
-    { expires: 60 * 60 * 24 },
+    { expires: 60 * 60 * 24 * 7 /* 1 week */ },
   );
 }