Display the real title screen behind the prelaunch menu (#638)

* Start game execution as soon as a disk image is available

* Do not update dDemo_c if prelaunch document is visible

* Prevent intro music until prelaunch has popped

* Replace "Start Game" references with "Play"

* Make prelaunch layout respect mirror mode

* Add drop shadow to prelaunch disk-status and version-info

* Remove ImGui prelaunch

* Add "Change Disk Image" button to prelaunch options

* Actually validate discs and make prelaunch very betterer :)

* Check your build before pushing dumbass, and go to sleep

* "Disc" consistency, adjust restart notice logic

* Better LanguageSelect logic

* Add restart notice to SaveTypeSelect

* Added wind sounds to the pre-launch menu

* Add Modal document, use it for disc verification

* Consolidate Modal and PresetWindow

* Squash various bugs, rearrange document flow

* Allow Window inheritors to opt-out of being toggleable

* Tweak focus behavior/syntax

* Implement "Restart Now" option

* Tweaks

* Remove a bunch of dynamic_cast

* Update README.md

---------

Co-authored-by: Luke Street <luke@street.dev>

include/dusk/main.h

@@ -1,6 +1,10 @@
 #ifndef DUSK_MAIN_H
 #define DUSK_MAIN_H
 
+#if defined(__APPLE__)
+#include <TargetConditionals.h>
+#endif
+
 #include <filesystem>
 
 namespace dusk {
@@ -8,7 +12,17 @@ namespace dusk {
     extern bool IsShuttingDown;
     extern bool IsGameLaunched;
     extern bool IsFocusPaused;
+    extern bool RestartRequested;
     extern std::filesystem::path ConfigPath;
+
+#if defined(__ANDROID__) || (defined(TARGET_OS_IOS) && TARGET_OS_IOS) || \
+    (defined(TARGET_OS_TV) && TARGET_OS_TV)
+    inline constexpr bool SupportsProcessRestart = false;
+#else
+    inline constexpr bool SupportsProcessRestart = true;
+#endif
+
+    void RequestRestart() noexcept;
 }
 
 #endif  // DUSK_MAIN_H