ci(website): remove deprecated next export; use next build with output: export

Author: alpha912

package.json

@@ -5,9 +5,8 @@
   "scripts": {
     "dev": "next dev",
     "build": "next build",
-    "export": "next export",
     "start": "next start",
-    "build:static": "next build && next export"
+    "build:static": "next build"
   },
   "dependencies": {
     "next": "^15.0.0",
@@ -21,4 +20,3 @@
     "@types/react-dom": "^18.3.0"
   }
 }
-