Windows/macOS runner images already ship the Android SDK; the only real
download was NDK 26.1.10909125. Align ANDROID_NDK_VERSION to the
preinstalled 27.3.13750724 so setup-android downloads nothing (zero cache
quota). Update setup-android-sdk.sh, Makefile and Readmes to match.
Emscripten is not preinstalled on ubuntu runners, so cache \C:\Users\xiaofans/emsdk
but only save on the default branch to avoid churning/evicting hot
per-PR caches.
- Updated CMakeLists.txt to include a new function for ensuring the third-party sources are checked out at configure time, improving build reliability.
- Added logic to handle different layouts for MoltenVK.xcframework in the resolve-vulkan-macos.sh script, ensuring compatibility with CI environments.
- Refined GitHub Actions workflows to streamline Android SDK setup and path resolution, enhancing the build process for Android targets.