ci: add mobile bindgen validation workflows

[pwltr]

Summary

• Add CI validation for Rust, shell scripts, and Clippy
• Add Android bindgen workflow that generates Kotlin/JNI artifacts on Ubuntu
• Add iOS bindgen workflow that generates Swift/XCFramework artifacts on macOS
• Upload generated mobile artifacts for inspection

Details

This is Phase 1 of moving mobile bindgen/release work into GitHub Actions.

The new workflows keep permissions read-only and do not publish packages, upload release assets, or remove any checked-in generated files. They only prove that Android and iOS generated outputs can be produced from source in CI.

See synonymdev/bitkit-core#114

Testing

Locally ran:

bash -n build.sh build_ios.sh build_android.sh build_python.sh

[pwltr]

Consumer verification

Downloaded the vss-ios-bindgen artifact from the iOS workflow run and used it in a temporary SwiftPM consumer package.

Verified:

• VssRustClientFfi.xcframework works as a local SwiftPM binary target
• generated vss_rust_client_ffi.swift imports and compiles against the FFI module
• downstream iOS simulator build succeeds

Command:

xcodebuild -scheme VssIosConsumer \
  -destination 'generic/platform=iOS Simulator' \
  build

[pwltr]

Android consumer verification

Downloaded the vss-android-bindgen artifact from the Android workflow run and used it in a temporary Android library consumer project.

Verified:

• generated Kotlin bindings compile in a separate Android project
• generated JNI .so files are packaged from jniLibs
• downstream Android debug AAR build succeeds

Command:

./gradlew :app:assembleDebug

[ovitrif]

Great work! 👏🏻

LGTM, looks thoroughly validated, lmk if I should revalidate locally on my machine, though it doesn't seem needed 🙏🏻