Add full offline Android Gradle Plugin dependency cache

tauri_app/docker/prefetch-android-agp.sh

@@ -11,6 +11,10 @@ copy_bundled() {
   if [ ! -f "${BUNDLED_ARTIFACT}" ]; then
     return 1
   fi
+  if [ ! -f "${BUNDLED_REPO}/com/android/tools/build/builder/${AGP_VERSION}/builder-${AGP_VERSION}.pom" ]; then
+    echo "Bundled AGP cache is incomplete (missing builder:${AGP_VERSION}). Run populate-offline-agp.sh on a machine with internet." >&2
+    return 1
+  fi
   mkdir -p "${LOCAL_REPO}"
   cp -a "${BUNDLED_REPO}/." "${LOCAL_REPO}/"
   echo "==> AGP ${AGP_VERSION} copied from bundled offline cache (${BUNDLED_REPO})"