Create target folder if it doesn't exist in the postinstall script.

npm-postinstall.mjs

@@ -1,12 +1,17 @@
-import { copyFileSync } from 'fs';
+import { copyFileSync, existsSync, mkdirSync } from 'fs';
 import { resolve, dirname } from 'path';
 import { fileURLToPath } from 'url';
 
 const filename = fileURLToPath(import.meta.url);
 const folder = dirname(filename);
 
 function copyFile(src, dest) {
-    copyFileSync(resolve(folder, src), resolve(folder, dest));
+    const target = resolve(folder, dest);
+    const targetFolder = dirname(target);
+    if (!existsSync(targetFolder))
+        mkdirSync(targetFolder, { recursive: true });
+
+    copyFileSync(resolve(folder, src), target);
     console.log(`Copied ${src} to ${dest}`);
 };