zalify/easy-email-editor ? reverse-engineered prompt

Build me a browser based email template editor in React that feels like a simple SaaS builder for marketing emails. I want people to be able to drag and drop blocks, edit the content visually, set a subject and subtitle, upload or paste images, and have the editor generate clean MJML based email code from what they build. Please include a nice full screen layout with the editor ready to use, plus a basic starter template so it does not open empty.

Keep it focused on the open source feature set, so basic editing is enough and it is okay if it mainly supports Chrome. I would also like a small demo page where I can load initial values, make changes, and inspect the current template data and generated code. Use sensible defaults like common fonts and autosave style behavior if that fits naturally.

If anything is unclear, look up the current docs online and wire it up in the simplest clean way.