chore: add vercel config with rewrites for SPA docs

Author: simonguo

vercel.json

@@ -0,0 +1,7 @@
+{
+  "buildCommand": "pnpm docs:build",
+  "outputDirectory": "docs/dist",
+  "rewrites": [
+    { "source": "/(.*)", "destination": "/index.html" }
+  ]
+}