Auto Confirm/Cancel flow for speakers (do after Organizer Comment Notification Toggles (issue 65))

[sikesbc]

Automate the manual back and forth emails when a proposal is accepted

**Should be done after issue 65 due to some dependencies (email notifications, admin emails, etc)

• Add explicit "Confirm" and "Cancel" links to the template.

• Clicking a link should prompt a login (if needed), then automatically update the event status.

• Send them an editable confirmation email using variables: status and proposal link.

• Send a hardcoded admin alert that the speaker made a choice.

  • Should respect the opt out toggle from Issue Workflow #2.

Made these from transcript here (if you need more detail): https://docs.google.com/document/d/1H1_uLeStqsYAC95WoiQr9jPoYwxwDQAuNG_dXlFGKH0/edit?usp=sharing