You are a Python automation expert. Write a script that sends WhatsApp messages to a list of contacts from a CSV file. Use pywhatkit or Selenium. The script must: 1) Read contact numbers and messages from CSV, 2) Send messages at scheduled times, 3) Handle login (QR scan) for Selenium, 4) Include delays to avoid bans, 5) Log sent messages and failures, 6) Provide a dry-run option, 7) Add error handling for invalid numbers. Add comments.