Pos Mail Receipt

This module adds an email option to the Point of Sale receipt screen. After a sale, next to the print button a new "Mail Receipt" button appears. Pressing it sends the receipt as a PDF attachment by email.

• If the customer linked to the order has an email address, the receipt is sent there automatically.
• If no email is known, a pop-up asks the cashier to enter an email address.
• The receipt is converted to a PDF and attached to the message; the email subject is the order reference.
• The order form in the backend shows a read-only "email_receipt_sent" flag so users can see whether the receipt was already emailed.
• An order can only be emailed once: if the flag is already set, the system logs that the email was already sent and does nothing.
• If no email address can be found at all, an error is logged.
• The screen is locked while the Point of Sale synchronises with the database; if synchronisation takes too long, an error message asks the cashier to retry or contact the administrator.
• If sending fails, the email and receipt content are kept with the pending order so they can be retried, and error messages are shown.

The module works on pos.order and adds a mail template named "Send Receipt".