Extract Win32 lifecycle state

src/platform_windows/windows_lifecycle_state.h

@@ -0,0 +1,16 @@
+#pragma once
+
+#include <Windows.h>
+
+#include <atomic>
+
+namespace pp::platform::windows {
+
+[[nodiscard]] std::atomic<int>& lifecycle_running_state() noexcept;
+void mark_lifecycle_running() noexcept;
+void mark_lifecycle_stopped() noexcept;
+[[nodiscard]] bool lifecycle_is_running() noexcept;
+[[nodiscard]] std::atomic<int>& retained_lifecycle_running_state() noexcept;
+[[nodiscard]] wchar_t* retained_window_fps_title_buffer() noexcept;
+
+}