feat: 支持自定义 Minecraft 窗口标题

全局开关 + 默认标题，实例可覆盖；Win32 重命名窗口。前端设置页同步。

packages/app-lib/src/launcher/mod.rs

@@ -1520,6 +1520,7 @@ pub async fn launch_minecraft(
     memory: &MemorySettings,
     resolution: &WindowSize,
     maximize_window: bool,
+    window_title: Option<String>,
     credentials: &Credentials,
     post_exit_hook: Option<String>,
     context: &InstanceLaunchContext,
@@ -2391,6 +2392,7 @@ pub async fn launch_minecraft(
             command,
             post_exit_hook,
             maximize_window,
+            window_title,
             instance_path.clone(),
             logs_folder,
             version_info.logging.is_some(),