chore(dev): add dev:webpack script as a Turbopack fallback

The chunk.reason.enqueueModel crash tracked in vercel/next.js#92362 is
Turbopack-specific — the React flight client in react-server-dom-turbopack
exposes an enqueueModel method that react-server-dom-webpack does not. Run

> client-board@0.1.0 dev:webpack
> next dev --webpack

▲ Next.js 16.2.6 (webpack)
- Local:         http://localhost:3000
- Network:       http://192.168.1.162:3000
- Environments: .env.local
✓ Ready in 554ms
[?25h while the upstream issue is open if the overlay
keeps catching the crash in spite of the ThemeScript / hydration fixes.

package.json

@@ -4,6 +4,7 @@
   "private": true,
   "scripts": {
     "dev": "next dev",
+    "dev:webpack": "next dev --webpack",
     "build": "next build",
     "start": "next start",
     "test": "vitest run --project unit",