A summary template would be a textbox where the user can input their own text to be used as a basis for the summary, with placeholders available to be replaced with actual values.

This change should also modify the "include attachments" and "include images" checkboxes on the options page to be a radio button group labelled "summary options" with the following options:

• "attachments only"
• "images only"
• "attachments and images"
• "custom template"

When the "custom summary template" radio button is selected, enable the custom summary template text box. This text box should be disabled unless the custom summary template is selected.

The summary template will have placeholders available, which will be replaced with content when copied to the clipboard:

• {{% links %}}
• {{% attachments %}}
• {{% images %}}
• {{% ticket_id %}}
• {{% ticket_url %}}