Clean up and segment email subscriber list

I've removed a total of 1,893 inactive contacts from the email list.

• Ran an engagement report for the last 30 days
• Identified contacts with a 0% open rate during that period
• Exported the list of inactive contacts to a CSV file
• Removed the inactive contacts from the main mailing list
• Updated the subscriber count in the email marketing platform
• Saved a backup of the removed contacts for future reference