Email Center: Custom Button Background Color, Header, Footer & Legal Info

🔍 Problem Statement

As a publisher, I can't customize email button colors or add footer content on automated emails, limiting brand and legal compliance control.

💡 User Story

As a publisher, I want automated email buttons to use my account's configured brand color, so my emails stay on-brand.

As a publisher, I want to add a custom header and footer to all automated emails, so I can include consistent supplementary content.

As a publisher, I want my company's legal name and address shown below the custom footer, so my emails meet legal disclosure requirements.

🎯 Definition of Done (DoD)

✔ Given an account has a brand color configured in site settings, when an automated email is sent, then all buttons in that email use the configured color as their background.

✔ Given a publisher has configured a custom header or footer, when any automated email is sent, then that footer renders below the email body.

✔ Given a publisher's legal name and address are configured, when any automated email is sent, then that info renders below the custom footer.

✔ This change will impact UI and API, specifically the Email Center settings and template rendering engine.

✔ This solution will include the following limitations: [clarify — is footer content limited to plain text/links, or does it support images; is legal name/address a new settings field or pulled from an existing one].