chore(studio): drop unused npm dependencies

Remove dotenv, shadcn, tw-animate-css, class-variance-authority — all
confirmed zero references in source after components/ui/ deletion.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/studio/package.json

@@ -32,16 +32,12 @@
     "@base-ui/react": "^1.3.0",
     "@fontsource-variable/geist": "^5.2.8",
     "@hono/node-server": "^1.13.0",
-    "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
-    "dotenv": "^16.4.0",
     "hono": "^4.7.0",
     "lucide-react": "^0.577.0",
     "react": "^19.0.0",
     "react-dom": "^19.0.0",
-    "shadcn": "^4.0.8",
-    "tailwind-merge": "^3.5.0",
-    "tw-animate-css": "^1.4.0"
+    "tailwind-merge": "^3.5.0"
   },
   "devDependencies": {
     "@tailwindcss/vite": "^4.0.0",