Add REST API documentation for Project Secret Key access

[devleejb]

Description:

Users can access the specified project via REST API using the Project Secret Key. For this functionality, it is necessary to include REST API Spec documentation in the project.

List of endpoints that need documentation:

• Document Creation
• Document Retrieval
• Document Listing
• Document Deletion

Reference:

• Liveblocks API Reference
• Supabase API Documentation

Why:

To provide users with a clear understanding of how to access and interact with the project using the REST API through the Project Secret Key.