Thin Win32 lifecycle close handling

docs/modernization/roadmap.md

@@ -124,6 +124,9 @@ Latest slice:
 - `src/platform_windows/windows_lifecycle_state.*` now also owns the Win32
   lifecycle close/VR control handoff, so `windows_lifecycle_shell.cpp` is
   down to a thinner message adapter over the retained lifecycle state helper.
+- `src/platform_windows/windows_lifecycle_state.*` now also owns the Win32
+  close-message shutdown/quit handoff, so `windows_lifecycle_shell.cpp` is
+  down to a one-line adapter over the retained lifecycle state helper.
 - `src/platform_windows/windows_runtime_shell.h` is now a thinner runtime
   entrypoint header that picks up the retained binding surface from
   `windows_runtime_state.h` instead of declaring a second shell-owned binding

docs/modernization/tasks.md

@@ -133,6 +133,9 @@ Current slice:
 - `src/platform_windows/windows_lifecycle_state.*` now also owns the Win32
   lifecycle close/VR control handoff, so `windows_lifecycle_shell.cpp` is
   down to a thinner message adapter over the retained lifecycle state helper.
+- `src/platform_windows/windows_lifecycle_state.*` now also owns the Win32
+  close-message shutdown/quit handoff, so `windows_lifecycle_shell.cpp` is
+  down to a one-line adapter over the retained lifecycle state helper.
 - `src/platform_windows/windows_runtime_shell.h` is thinner again and now
   imports that binding surface from `windows_runtime_state.h` instead of
   declaring shell-owned bind/release accessors itself.

src/platform_windows/windows_lifecycle_shell.cpp

@@ -16,8 +16,7 @@ void request_window_close(HWND hWnd)
 
 void handle_window_close_message(VrShellState& vr)
 {
-    shutdown_bound_lifecycle(vr);
-    PostQuitMessage(0);
+    shutdown_bound_lifecycle_and_quit(vr);
 }
 
 void update_stylus_frame(float dt)

src/platform_windows/windows_lifecycle_state.cpp

@@ -46,6 +46,12 @@ void shutdown_bound_lifecycle(VrShellState& vr)
     shutdown_bound_app_runtime();
 }
 
+void shutdown_bound_lifecycle_and_quit(VrShellState& vr)
+{
+    shutdown_bound_lifecycle(vr);
+    PostQuitMessage(0);
+}
+
 bool start_bound_lifecycle_vr(VrShellState& vr, bool sandboxed)
 {
     return start_vr_shell(vr, sandboxed, retained_lifecycle_running_state());

src/platform_windows/windows_lifecycle_state.h

@@ -13,6 +13,7 @@ void mark_lifecycle_stopped() noexcept;
 [[nodiscard]] bool lifecycle_is_running() noexcept;
 [[nodiscard]] std::atomic<int>& retained_lifecycle_running_state() noexcept;
 void shutdown_bound_lifecycle(VrShellState& vr);
+void shutdown_bound_lifecycle_and_quit(VrShellState& vr);
 [[nodiscard]] bool start_bound_lifecycle_vr(VrShellState& vr, bool sandboxed);
 void stop_bound_lifecycle_vr(VrShellState& vr);