• Notification Center: Fixed browser language auto-save overwriting contact's manually chosen language. Now only auto-detects when contact has no language set.
• Email Builder: Fixed missing MJML component defaults (border-radius, borders, background, direction, textAlign) causing styles not to render in the WYSIWYG editor
• Transactional Emails: Added subject override to email_options, allowing dynamic email subject lines per API call with Liquid templating support (#281)