feat(launcher): offer local and Remote Play launch choices

docs/launcher.md

@@ -51,3 +51,7 @@ The result shows RMS target bias and the worst target bias in degrees. Each targ
 After substantial changes to headset fit or the window distance, run calibration again.
 
 Press feedback appears only after holding for 200 ms. The Dock entry uses a blue border indicator and opens the quick panel at 600 ms. Launcher icons show a translucent white circular progress border: the halfway tick opens the menu at 400 ms; continuing to 800 ms enters icon editing. Release or cancellation removes the indicator.
+
+### Remote Steam games
+
+The Steam category also shows apps installed on a connected Remote Play computer. A small Remote Play badge appears at the bottom right of their icons. The list refreshes in the background; disconnected hosts disappear, and each App ID has one icon. If both local and remote installations are available, clicking it opens a choice between launching locally and Remote Play. Favorites and manual ordering remain shared for that game. Clicking a remote icon asks Steam to stream from its current host and checks availability again before launching. Artwork uses the local Steam cache, with a placeholder when unavailable. The integration uses the running Steam client UI; if that interface is unavailable, local games remain usable.

docs/zh-CN/launcher.md

@@ -53,3 +53,7 @@ Steam 启动成功表示请求已交给 Steam，并不代表游戏加载完成
 明显调整头显佩戴方式或窗口距离后，请重新校准。
 
 按住 200 毫秒后才显示进度反馈。Dock 入口使用蓝色边框进度，600 毫秒打开快捷面板。启动台图标使用半透明白色圆形边框进度：中点刻度对应 400 毫秒打开菜单，继续按至 800 毫秒进入图标编辑；松手或取消按压后移除进度。
+
+### Steam 远程畅玩
+
+Steam 分类也显示已连接远程畅玩电脑上安装的应用，图标右下角标有远程图标。列表后台刷新，断连的电脑不再展示；相同 App ID 只显示一个图标；本机和远程都可用时，点击弹窗选择本机启动或远程畅玩，收藏和手动排序保持同一份。点击远程图标会先重新检查可用状态，再让 Steam 从对应电脑串流。图片使用本机 Steam 缓存，缺图显示占位图。此功能读取正在运行的 Steam 客户端界面；该接口不可用时，本机游戏仍可使用。