Feat: A major changes includes: Builder UI for emails, slack

[kriss145]

MPN Builder UI

This PR introduces a complete rebuild of the notification templates system with a new MPN Builder module, full UI builder, Slack Block Kit support, and comprehensive template management capabilities.

Breaking Changes

API Routes Changed

All API endpoints moved from /api/admin/notification-plugin/ to /api/admin/mpn/. Update all API integrations.

Admin UI Routes Changed

Admin UI routes changed from /notifications-emails/ to /mpn/notifications/. Update all Admin UI links/bookmarks.

Module Restructure

Modules moved from templates/ to modules/mpn-builder/. Update all direct imports from templates/.

Old Workflows Removed

Removed old workflows (email-service, mpn-templates/*). Migrate to new mpn-builder/* workflows.

Email and Slack Service Import Changed

Changed import and execution method:

Before:

import { emailService } from "../templates/emails"
await emailService.render(...)

After:

import { emailServiceWorkflow } from "../workflows/mpn-builder-services/email-service"
await emailServiceWorkflow(container).run({...})

Template ID Handling Changed

Template ID handling changed - system_ prefix removed from UI display (still used internally), unified to kebab-case format.

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New Features

MPN Builder Module

Complete mpn-builder module with template management (services, models, 3 migrations).

UI Builder for Templates

Full-featured UI builder with drag & drop, inline editing, template preview, and support for multiple block types (heading, text, row, separator, group, repeater, product-item).

Slack Block Kit Support

Complete Slack Block Kit format support with block transformation, data interpolation, and nested structures.

External Templates Support

Support for external templates with type filtering (system, db, external). Configure via medusa-config.ts:

{
  resolve: "@codee-sh/medusa-plugin-notification-emails",
  options: {
    extend: {
      services: [{
        id: "slack",
        templates: [{
          name: "external_template-name",
          path: path.resolve(require.resolve("@package/templates/slack/template"))
        }]
      }]
    }
  }
}

New Block Types

Support for group, repeater, and product-item blocks with recursive rendering and data interpolation.

New Workflows and Steps

Added 10+ workflows for template management (create, edit, delete, get templates/blocks/services/types) with full JSDoc documentation.

Helper Components

Added helper components (ManagerFields, TwoColumnPage, form fields).

Store and Region Workflows

Added workflows for retrieving Store and Region data for template preview context.

API Middleware

Added middleware for API routing (error handling, request validation).

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Improvements

• Code refactoring (standardized naming, renamed methods, removed unused code)
• Template ID handling fixes (unified format, kebab-case)
• Fixed block data structure (added parent_id support, arrayPath for repeaters)
• Added JSDoc documentation for all workflows and steps
• UI improvements (button sizes, field descriptions, two-column layout)
• Improved data handling (added region to queries, improved filtering)
• Added new UI dependencies (@dnd-kit/core, @lexical/*, @react-email/*, react-email)

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Testing Checklist

• Test API endpoints migration (/api/admin/mpn/*)
• Test Admin UI routes (/mpn/notifications/*, /mpn/templates/*)
• Test template creation/editing/deletion via UI
• Test block drag & drop functionality
• Test Slack Block Kit rendering
• Test external templates configuration
• Test email/Slack service workflow migration
• Test template ID handling (system/db/external)

Documentation

• Changeset created (.changeset/major-release-builder-ui.md)
• JSDoc added to all workflows and steps