irkartik/MassEmailer — reverse-engineered prompt

Build me a simple mass email sender that I can run from my computer. I want to put a list of email addresses in a CSV file, write the email body in an HTML template, add a subject and sender login details, then send the same email to everyone in the list.

Please make it friendly for someone who is not very technical. Include clear setup steps, a sample CSV, a sample HTML email template, and a simple way to edit the sender email, password or app password, subject, and SMTP settings. It should show progress while sending, skip blank or invalid email addresses, and print a clear message if something goes wrong.

Keep it lightweight and easy to understand. Python is fine for the sending script, and the email body can come from an HTML file. Add comments in the code so I can change the template and recipient file later.