🔧 chore(scripts): set default port for preview command

- add PORT=8080 to preview script to ensure consistent port usage during preview
- makes local preview experience more predictable without manual port configuration

package.json

@@ -8,7 +8,7 @@
     "build": "npm run build:client && npm run build:server",
     "build:client": "vite build --outDir dist/client",
     "build:server": "vite build --ssr src/entry-server.tsx --outDir dist/server",
-    "preview": "cross-env NODE_ENV=production node server"
+    "preview": "PORT=8080 cross-env NODE_ENV=production node server"
   },
   "dependencies": {
     "compression": "^1.8.0",