Publish desktop updater 1.0.0-alpha.3

nodejs/README.md

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+# vtracer (Node.js)
+
+Raster → vector (SVG) for Node, a WebAssembly build of the
+[`vtracer`](https://github.com/visioncortex/vtracer) framework. Image decoding
+and vectorization both happen in wasm, so there is **no native dependency** —
+just `npm install`.
+
+## Install
+
+```sh
+npm install @visioncortex/vtracer
+```
+
+## Usage
+
+```js
+const vtracer = require('@visioncortex/vtracer');
+
+// file in, file out
+await vtracer.convertFile('in.png', 'out.svg');
+await vtracer.convertFile('in.jpg', 'out.svg', { mode: 'polygon', hierarchical: 'cutout' });
+
+// buffers
+const svg = vtracer.convertBuffer(fs.readFileSync('in.png'), { preset: 'poster' });
+
+// raw RGBA8 pixels
+const svg2 = vtracer.convertPixels(rgba, width, height, { clustering: 'bw' });
+```
+
+## API
+
+- `convertBuffer(buffer, options?) => string` — encoded image (PNG/JPEG/GIF/BMP) → SVG.
+- `convertPixels(rgba, width, height, options?) => string` — raw RGBA8 → SVG.
+- `convertFile(input, output, options?) => Promise<void>` — read, trace, write.
+- `convertFileSync(input, output, options?) => void`.
+
+### `Options` (all optional, camelCase)
+
+`preset` (`"bw" | "poster" | "photo"`, applied first), `clustering`
+(`"color-cluster" | "bw" | "watershed"`), `hierarchical` (`"stacked" | "cutout"`
+for the seam-free mosaic), `mode` (`"pixel" | "polygon" | "spline"`),
+`filterSpeckle`, `colorPrecision`, `layerDifference`, `cornerThreshold`,
+`lengthThreshold`, `maxIterations`, `spliceThreshold`, `simplify` (curve
+simplification tolerance in px, try 1–2.5), `pathPrecision`, `palette` (list of
+`#rrggbb`), `maxColors`, `optimize` (`0 | 1 | 2`), `binaryThreshold` /
+`adaptive` / `adaptiveWindow` / `adaptiveT` (binary mode), `watershedDetail`
+(0..=255).
+
+## Build from source
+
+Requires the Rust toolchain and [`wasm-pack`](https://rustwasm.github.io/wasm-pack/):
+
+```sh
+npm run build   # wasm-pack build --target nodejs --out-dir pkg
+npm test
+```