Schedule Future Sending of Templates

Often during a conversation, a customer indicates that they would like to be contacted in the future. It would be helpful to schedule that follow-up message for the date the customer specifies.

Currently, I handle this by changing the stage and using a workflow, but it could be a native feature—the `send_template` function could have an input variable specifying the date. If it’s empty, it sends the message immediately; if it has a value, it sends it on the specified date and time. Just like how “Schedule-ai-call” works today.