Abilities API: Register Kit MCP Server

[n7studios]

Summary

Registers a Kit MCP Server within WordPress, on which abilities (WordPress' term for MCP tools), resources and prompts can later be registered.

WordPress doesn't (yet) ship with native MCP server support; this is provided by the WordPress MCP Adapter Plugin, included via composer as we do for the Kit WordPress Libraries.

Future PRs to cover:

• registering abilities (MCP Tools)
• registering resources
• tests

Testing

• MCPTest: Tests that the Kit MCP Server is registered by querying the WP REST API, both as an unauthorized user (401) and as an administrator (200 with expected server info).

Checklist

• I have written a test and included it in this PR
• I have run all tests and they pass
• The code passes when running the PHP CodeSniffer
• Code meets WordPress Coding Standards for PHP, HTML, CSS and JS
• Security and Sanitization requirements have been followed
• I have assigned a reviewer or two to review this PR (if you're not sure who to assign, we can do this step for you)