Challenge: Build a SIWS Message

Construct a properly formatted Sign-In With Solana (SIWS) message that can be used for authentication.

Requirements

• Create a function that accepts domain (string), publicKey (PublicKey), nonce (string), and statement (string)
• Generate an ISO timestamp for "Issued At" (use new Date().toISOString())
• Return a formatted SIWS message string following this structure:

  {domain} wants you to sign in with your Solana account:
  {publicKey}
  
  {statement}
  
  URI: https://{domain}
  Version: 1
  Nonce: {nonce}
  Issued At: {issuedAt}
  

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