Fix Quest launch crashes, version the APK like the tarball, and support native builds in Android Studio

- patchelf gl4es's embedded SONAME to libGL.so so AGP's jniLibs packaging
  (which drops any file not literally named "*.so") and the dynamic
  linker's NEEDED-entry resolution (by embedded SONAME, not filename)
  finally agree - fixes the "library \"libGL.so.1\" not found" crash seen
  on real Quest hardware.
- QuestShockActivity now checks that res/data and res/sound exist before
  starting the native engine, showing an explanatory dialog instead of
  crashing on init_popups' unchecked NULL resource load when a fresh
  install has no game data copied in yet.
- dist/questshock-<version>-android-arm64.apk is now versioned from the
  same git-tag-or-dev-placeholder scheme as the desktop tarball
  (build-image/version.sh, shared by both via the Makefile and
  build-apk.sh).
- build-image/prepare-android-project.sh (prep logic extracted out of
  build-apk.sh) can now stage android/ for a native build directly in
  Android Studio (--host-paths), exporting the prebuilt SDL2/SDL2_mixer/
  fluidsynth-lite/gl4es libraries and writing host-resolvable paths,
  instead of only ever building inside the Docker image.
- Corrected GET_ASSETS.txt/GET_ASSETS_QUEST.txt, which wrongly described
  merging res/pc/hd and res/pc/cdrom trees out of the raw installer's
  sshock.kpf - an already-installed copy's res/data res/sound can just
  be copied directly, with extract_assets.sh only needed from the raw
  installer.

res/assets/GET_ASSETS_QUEST.txt

@@ -1,17 +1,14 @@
 This app does not include System Shock's game data - it's copyrighted,
-proprietary content that can't be redistributed. To play, you need a
-copy of System Shock: Enhanced Edition (e.g. from gog.com).
-
-From your Enhanced Edition install, you need its classic-game data and
-sound files - the res/pc/hd/data and res/pc/cdrom/data trees merged
-together (res/pc/hd's copies win the couple of filenames present in
-both: intro.res, objprop.dat), and the res/pc/hd/sound tree, packed
-inside the install's sshock.kpf (a zip file).
+proprietary content that can't be redistributed. To play, you need to
+own a copy of System Shock: Enhanced Edition (e.g. from gog.com),
+installed (on Windows, or via Wine/Proton on Linux).
 
 Using SideQuest (or any MTP file browser) with your Quest connected,
-copy that merged data into:
+copy its res/data/ and res/sound/ folders directly into:
   /sdcard/questshock/res/data/
   /sdcard/questshock/res/sound/
+They already contain everything needed, in the right layout - no
+merging or extraction required.
 
 (shaders/ and this app's default soundfont are already here, extracted
 automatically on first launch - only res/data/ and res/sound/ are