chore: scaffold Vite + React 19 + Tailwind v4 app on HMDesign

Start the React rebuild of the DWG/DXF viewer (#1).

- HMDesign is a git submodule (vendor/HMDesign, main) and its
  packages/ui is an npm workspace, so @hm-design/ui resolves to the
  submodule and shares this repo's node_modules.
- scripts/setup-hmdesign.mjs (postinstall) builds the package dist and
  points vendor/HMDesign/node_modules at ours with a junction, because
  HMDesign's build script reads typescript/shadcn from its own root.
  Nothing inside the submodule is modified.
- Versions follow HMDesign (react 19.3.0, vite 8.3.0, tailwindcss
  4.3.3, typescript 7.0.2) and the sample (three 0.185.1, dxf-parser
  1.1.2, opentype.js 2.0.0).
- CSS entry: tailwindcss + @hm-design/ui/tailwind.css (index.css).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

package.json

@@ -0,0 +1,42 @@
+{
+  "name": "dwg-dxf-viewer-hm",
+  "private": true,
+  "version": "0.2.0",
+  "description": "DWG/DXF 2D viewer: the dwg-dxf-viewer-sample engine (Viewer2D + acadrust-dwg + dxf-parser) inside a React 19 app built on HMDesign (@hm-design/ui).",
+  "type": "module",
+  "workspaces": [
+    "vendor/HMDesign/packages/ui"
+  ],
+  "scripts": {
+    "postinstall": "node scripts/setup-hmdesign.mjs",
+    "hm:build": "node scripts/setup-hmdesign.mjs --force",
+    "dev": "vite --port 5173 --strictPort",
+    "build": "tsc -p tsconfig.json && vite build",
+    "preview": "vite preview --port 4173 --strictPort",
+    "typecheck": "tsc -p tsconfig.json",
+    "guard": "node vendor/HMDesign/scripts/ai-generation-guard.mjs --target . --scope FULL_SCREEN --mode GNB_ONLY --result index.html"
+  },
+  "dependencies": {
+    "@hm-design/ui": "*",
+    "dxf-parser": "1.1.2",
+    "lucide-react": "1.49.0",
+    "opentype.js": "2.0.0",
+    "react": "19.3.0",
+    "react-dom": "19.3.0",
+    "three": "0.185.1"
+  },
+  "devDependencies": {
+    "@babel/parser": "7.29.9",
+    "@tailwindcss/vite": "4.3.3",
+    "@types/node": "24.7.0",
+    "@types/react": "19.3.0",
+    "@types/react-dom": "19.3.0",
+    "@types/three": "0.185.1",
+    "@vitejs/plugin-react": "6.1.1",
+    "fast-glob": "3.3.3",
+    "postcss": "8.5.28",
+    "tailwindcss": "4.3.3",
+    "typescript": "7.0.2",
+    "vite": "8.3.0"
+  }
+}