fix(windows): use rename fallback for WSL UNC

src-tauri/src/config.rs

@@ -423,61 +423,10 @@ pub fn atomic_write(path: &Path, data: &[u8]) -> Result<(), AppError> {
 
             let replace_error = std::io::Error::last_os_error();
             // WSL UNC paths reject ReplaceFileW with ERROR_NOT_SUPPORTED (50).
-            // Fall back to rename-based replacement with a rollback backup there.
+            // std::fs::rename uses a different replace-existing API on Windows.
             let replace_not_supported =
                 replace_error.raw_os_error() == Some(ERROR_NOT_SUPPORTED as i32);
-            if replace_not_supported {
-                let mut backup_name = tmp
-                    .file_name()
-                    .expect("temporary path must have a file name")
-                    .to_os_string();
-                backup_name.push(".backup");
-                let backup = tmp.with_file_name(backup_name);
-                let backup_created = match fs::rename(path, &backup) {
-                    Ok(()) => true,
-                    Err(source) if source.kind() == std::io::ErrorKind::NotFound => false,
-                    Err(source) => {
-                        last_error = Some(source);
-                        break;
-                    }
-                };
-
-                match fs::rename(&tmp, path) {
-                    Ok(()) => {
-                        if backup_created {
-                            if let Err(source) = fs::remove_file(&backup) {
-                                log::warn!(
-                                    "Failed to remove atomic-write backup {}: {}",
-                                    backup.display(),
-                                    source
-                                );
-                            }
-                        }
-                        completed = true;
-                        break;
-                    }
-                    Err(source) => {
-                        if backup_created {
-                            if let Err(restore_error) = fs::rename(&backup, path) {
-                                return Err(AppError::IoContext {
-                                    context: format!(
-                                        "原子替换及回滚失败: {} -> {}; 原文件保留在 {}; 回滚错误: {}",
-                                        tmp.display(),
-                                        path.display(),
-                                        backup.display(),
-                                        restore_error
-                                    ),
-                                    source,
-                                });
-                            }
-                        }
-                        last_error = Some(source);
-                        break;
-                    }
-                }
-            }
-
-            if replace_error.kind() != std::io::ErrorKind::NotFound {
+            if replace_error.kind() != std::io::ErrorKind::NotFound && !replace_not_supported {
                 last_error = Some(replace_error);
                 break;
             }