fix: 根目录 404 问题

Author: NoraH1to

vercel.json

@@ -1,6 +1,8 @@
 {
   "rewrites": [
     { "source": "/proxy/:match/:url*", "destination": "https://:match/:url*" },
-    { "source": "/httpproxy/:match/:url*", "destination": "http://:match/:url*" }
+    { "source": "/proxy/:match/:url*/", "destination": "https://:match/:url*/" },
+    { "source": "/httpproxy/:match/:url*", "destination": "http://:match/:url*" },
+    { "source": "/httpproxy/:match/:url*/", "destination": "http://:match/:url*/" }
   ]
 }