Add custom entity feature

[Lynn-Bing]

Summary

Implement custom entity management UI with add/delete functionality

Description

This PR introduces a new user interface for managing custom entities. It includes the ability to add and delete entities, along with the necessary backend integration to ensure these operations are synchronized with the server.

Changes

• Frontend:
  • Create a new UI component for displaying custom entities
  • Implement forms for adding new entities
  • Implement deletion functionality with confirmation dialogs
  • Add success and error notifications for add/delete operations
• Backend Integration:
  • Add API endpoints for creating and deleting entities
  • Integrate frontend with backend API for add/delete operations
  • Ensure real-time updates to the entity list after add/delete actions

UI Screenshots

Add Entity Form

Entity List with Delete Option