Add vercel.json configuration to fix 404 errors

Co-authored-by: huangyiirene <7665279+huangyiirene@users.noreply.github.com>

Author: Copilot

vercel.json

@@ -0,0 +1,9 @@
+{
+  "redirects": [
+    {
+      "source": "/",
+      "destination": "/en/docs",
+      "permanent": false
+    }
+  ]
+}