chore(web): set dev port to 3001 to avoid gateway conflict

Gateway occupies port 3000, so the Next.js dev server now
runs on port 3001.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/web/package.json

@@ -3,7 +3,7 @@
   "version": "0.1.0",
   "private": true,
   "scripts": {
-    "dev": "next dev",
+    "dev": "next dev --port 3001",
     "build": "next build",
     "start": "next start",
     "lint": "eslint"