Add a QuestShock startup splash; rename the app and data folder

android/app/src/main/cpp/qs_splash.h

@@ -0,0 +1,15 @@
+// Startup splash: the QuestShock title, shown on the game screen before the
+// engine's own splash sequence.
+#pragma once
+
+#include <stdint.h>
+
+// Stores a copy of the splash image (straight-alpha ARGB, one int per pixel).
+// Called from JNI before the engine starts; replaces any earlier image. Without
+// an image qs_splash_show() does nothing.
+void qs_splash_set_image(const uint32_t *argb, int width, int height);
+
+// Engine thread only (called from engine patch 27). Fades the image in and out
+// on the game screen and returns when done, or after a few seconds if the XR
+// session never starts.
+void qs_splash_show(void);