The Android/Quest CMakeLists.txt patch previously reimplemented desktop

immediate-mode GL (glBegin/glVertex3f/glEnd and friends) from scratch on
top of GLES, since GLES has none of it. That code compiled but was never
actually exercised - no on-screen verification was possible without real
Quest hardware - making it the biggest unverified risk in the port.

Replace it with GL4ES (MIT-licensed, prebuilt into the build image),
a mature desktop-GL-on-GLES translation library used by other
Quest/Android game ports for exactly this problem. This cuts
04-android-opengl-es-render.patch by half, deleting the hand-written
vertex-accumulation emulation entirely; alpha test, point sprites, and
point size stay on their existing GLES-native fixes rather than trusting
GL4ES's shakier custom-shader interop for those.

Bump build-image/VERSION to 3 - a fresh image with GL4ES cross-compiled
for arm64-v8a was built and make apk verified successfully against it.

README.md

@@ -110,6 +110,11 @@ the [MIT License](LICENSE).
 [SDL2](https://www.libsdl.org/)'s own android-project template and is
 zlib-licensed, same as SDL2 itself.
 
+The Quest build also bundles [GL4ES](https://github.com/ptitSeb/gl4es)
+(`lib/arm64-v8a/libGL.so` in the APK, prebuilt unmodified into the build
+image), which translates the engine's desktop-style OpenGL calls into
+GLES/EGL and is MIT-licensed.
+
 The vendored engine snapshot in `engine/` is
 [Shockolate](https://github.com/Interrupt/systemshock), which is licensed
 under the **GNU GPLv3** (see `engine/LICENSE`) - it is included unchanged