React Email 6.0 adds embeddable editor

This is a meaningful platform shift, not just a version bump: Resend is trying to own both the code-first and no-code sides of email creation.

• –The embeddable editor is the real headline; it makes React Email useful for products that want to offer email building inside their own UI.
• –Custom extensions via `EmailNode` give teams a way to add product-specific blocks without forking the editor.
• –The unified `react-email` package simplifies imports and should reduce friction for existing users migrating from the older split-package setup.
• –New templates make the ecosystem more immediately usable for auth and e-commerce flows, which are the highest-value email use cases for most apps.
• –This reinforces Resend’s positioning as an email platform for developers, not just a sending API.