Fixes#696
- Replaced sharp dependency with wasm-vips (WebAssembly build of libvips)
- Eliminates native build requirements that caused installation failures
- Added vips.ts singleton wrapper for async initialization
- Updated image-resize.ts and image-convert.ts to use wasm-vips API
- Added unit tests for image processing functionality
JPEG/GIF/WebP images were not rendering in terminals using the Kitty
graphics protocol (Kitty, Ghostty, WezTerm) because it requires PNG
format (f=100). Non-PNG images are now converted to PNG using sharp
before being sent to the terminal.