refactor: establish unified viewer workspaces

apps/viewer-2d-sample/vite.config.ts

@@ -0,0 +1,12 @@
+import { defineConfig } from 'vite';
+
+export default defineConfig({
+  server: {
+    port: 5173,
+    strictPort: true,
+  },
+  optimizeDeps: {
+    include: ['three', 'dxf-parser', 'opentype.js'],
+  },
+  assetsInclude: ['**/*.wasm'],
+});