fix: handle CJS default export in ESM context for dir-is-case-sensitive test

Node 22+ runs .ts files natively as ESM via type stripping, where
importing a CJS module with exports.default doesn't auto-unwrap.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: zkochan

dir-is-case-sensitive/test/index.ts

@@ -1,6 +1,8 @@
-import dirIsCaseSensitive from 'dir-is-case-sensitive'
+import dirIsCaseSensitiveModule from 'dir-is-case-sensitive'
 import test from 'tape'
 
+const dirIsCaseSensitive = dirIsCaseSensitiveModule.default ?? dirIsCaseSensitiveModule
+
 test('dirIsCaseSensitive()', async (t) => {
   const isCaseSensitive = await dirIsCaseSensitive(import.meta.dirname)
   t.equal(typeof isCaseSensitive, 'boolean')