Include Magic links in sendgrid templates

🔍 Problem Statement

Magic links (passwordless login URLs) cannot be included in custom SendGrid email templates. Clients who use SendGrid for transactional emails have no way to embed a magic link dynamically, forcing them to use Pelcro's default email templates.

💡 User Story

As a Pelcro admin using SendGrid, I want to include magic link URLs as variables in custom SendGrid templates, so that passwordless login emails match our brand and design.

🎯 Definition of Done (DoD)

A feature is done when:

✔️ Given a SendGrid email template, when the admin includes the magic link variable, then the email is sent with a valid, functional magic link URL embedded — and the link works identically to Pelcro's default magic link emails.