Replace sharp with wasm-vips for image processing

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

packages/coding-agent/package.json

@@ -51,7 +51,7 @@
 		"marked": "^15.0.12",
 		"minimatch": "^10.1.1",
 		"proper-lockfile": "^4.1.2",
-		"sharp": "^0.34.2"
+		"wasm-vips": "^0.0.16"
 	},
 	"devDependencies": {
 		"@types/diff": "^7.0.2",