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

modules/repository/init.go

@@ -81,7 +81,7 @@ func LoadRepoConfig() error {
 		if isDir, err := util.IsDir(customPath); err != nil {
 			return fmt.Errorf("failed to check custom %s dir: %w", t, err)
 		} else if isDir {
-			if typeFiles[i].custom, err = util.StatDir(customPath); err != nil {
+			if typeFiles[i].custom, err = util.ListDirRecursively(customPath, &util.ListDirOptions{SkipCommonHiddenNames: true}); err != nil {
 				return fmt.Errorf("failed to list custom %s files: %w", t, err)
 			}
 		}