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.

run-image.sh

@@ -39,11 +39,17 @@ docker image inspect "$IMAGE" >/dev/null 2>&1 \
 TTY_FLAGS="-i"
 [ -t 1 ] && TTY_FLAGS="-it"
 
+# HOST_REPO_ROOT: lets scripts running in the container (e.g.
+# build-image/prepare-android-project.sh --host-paths) write paths that
+# resolve on the HOST filesystem instead of this container's own
+# /workspace - needed so a gradlew/Android Studio running natively on the
+# host afterwards can find them.
 # shellcheck disable=SC2086
 docker run --rm $TTY_FLAGS \
     -v "$ROOT:/workspace" \
     -e HOST_UID="$(id -u)" \
     -e HOST_GID="$(id -g)" \
+    -e HOST_REPO_ROOT="$ROOT" \
     "$IMAGE" \
     "$@"