feat: ship Barkstack UI plugin

ui/vite.config.ts

@@ -0,0 +1,18 @@
+import { svelte } from '@sveltejs/vite-plugin-svelte';
+import { defineConfig } from 'vite';
+import { resolve } from 'node:path';
+
+export default defineConfig({
+  plugins: [svelte({ compilerOptions: { customElement: true } })],
+  build: {
+    lib: {
+      entry: resolve(__dirname, 'src/entry.ts'),
+      formats: ['es'],
+      fileName: () => 'assets/entry.js'
+    },
+    outDir: '../internal/adminui/dist',
+    emptyOutDir: true,
+    target: 'es2022'
+  },
+  test: { environment: 'jsdom' }
+});