move hs2js package here + improve readme

packages/hs2js/vite.config.mjs

@@ -0,0 +1,20 @@
+import { defineConfig } from "vite";
+import { resolve } from "path";
+
+// https://vitejs.dev/config/
+export default defineConfig({
+  plugins: [],
+  build: {
+    lib: {
+      entry: resolve(__dirname, "src", "index.mjs"),
+      name: "hs2js",
+      formats: ["es", "iife"],
+      fileName: (ext) => ({ es: "index.mjs", iife: "index.js" }[ext]),
+    },
+    rollupOptions: {
+      // external: [...Object.keys(dependencies)],
+      plugins: [],
+    },
+    target: "esnext",
+  },
+});