Port image processing from Oh My Pi's pi-natives crate, adapted for napi-rs v2.
Exposes NativeImage class with async parse/encode/resize methods backed by the
Rust `image` crate (PNG, JPEG, WebP, GIF support).
Includes:
- task.rs: lightweight async task scheduling for libuv thread pool
- image.rs: NativeImage class with SamplingFilter enum
- TypeScript types and wrapper (parseImage, ImageFormat, SamplingFilter)
- 8 passing tests covering decode, encode, resize, round-trip, error cases
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
