try(settings): 尝试修正快捷键弹窗协程生命周期（编译通过，待验证） / Try correcting shortcut dialog coroutine lifetime (build passed, validation pending)

中文：
- 让快捷键弹窗协程按值持有共享状态，避免 ShowAsync 完成时访问已经失效的引用
- 增加源码契约测试，禁止异步弹窗恢复依赖引用参数

English:
- Make the shortcut dialog coroutine own shared state by value so the ShowAsync continuation cannot access an expired reference
- Add a source contract test that rejects reference parameters for the asynchronous dialog continuation

验证 / Validation:
- scripts/build.bat --reload-shell（Release 构建通过，已生成 .build\\Release\\SnowDesktop.exe / Release build passed and generated .build\\Release\\SnowDesktop.exe）
- scripts/test.bat（103/103 通过 / 103/103 passed）

限制 / Limitations:
- 修正后的回车应用场景尚待用户实机复测 / The corrected Enter-to-apply scenario still requires user runtime validation

Author: FreeFallingSnow

src/winui/hotkey_recorder.cpp

@@ -583,7 +583,7 @@ void ApplyTransition(
 }
 
 winrt::fire_and_forget ShowShortcutDialog(
-    const std::shared_ptr<HotkeyRecorderState>& state)
+    std::shared_ptr<HotkeyRecorderState> state)
 {
     if (!state || !state->alive || !state->enabled || state->dialogOpen)
         co_return;

tests/winui_settings_navigation_tests.cpp

@@ -800,6 +800,12 @@ void TestGeneralPageSourceContract(const std::filesystem::path& root)
             recorder.find(
               "dialog.DefaultButton(muxc::ContentDialogButton::Primary)") !=
                 std::string::npos &&
+            recorder.find(
+              "ShowShortcutDialog(\n    std::shared_ptr<HotkeyRecorderState> state)") !=
+                std::string::npos &&
+            recorder.find(
+              "ShowShortcutDialog(\n    const std::shared_ptr<HotkeyRecorderState>& state)") ==
+                std::string::npos &&
             recorder.find("co_await state->dialog.ShowAsync()") !=
                 std::string::npos &&
             recorder.find("captureSurface.KeyDown") !=