fix hydration error

app/src/components/WalletButton.tsx

@@ -1,9 +1,13 @@
 'use client'
 
-import React from 'react'
+import { useState, useEffect } from 'react'
 import { WalletMultiButton } from '@solana/wallet-adapter-react-ui'
 
 export function WalletButton() {
+  const [mounted, setMounted] = useState(false)
+  useEffect(() => setMounted(true), [])
+  if (!mounted) return null
+
   return (
     <WalletMultiButton
       style={{