Fix unittest and repo create bug (#33061)

1. `StatDir` was not right, fix the FIXME
2. Clarify the test cases for `IsUsableRepoName`
3. Fix regression bug in `repo-new.ts`

Fix #33060

web_src/js/features/repo-new.ts

@@ -11,7 +11,8 @@ export function initRepoNew() {
   const updateUiAutoInit = () => {
     inputAutoInit.checked = Boolean(inputGitIgnores.value || inputLicense.value);
   };
-  form.addEventListener('change', updateUiAutoInit);
+  inputGitIgnores.addEventListener('change', updateUiAutoInit);
+  inputLicense.addEventListener('change', updateUiAutoInit);
   updateUiAutoInit();
 
   const inputRepoName = form.querySelector<HTMLInputElement>('input[name="repo_name"]');