Support enabling MCP Tools in Cursor Rules

We often write specific workflows as cursor rules. These rules refer to tools explicitly to improve the likelihood of invocation. It would be good to be able to enable MCP servers + their tools as part of the rule’s definition.

Example:

Use the `search_github_pull_requests` tool to search for the most recently opened web-api upgrade PR, by using the following args.
{
  "time_range": "yesterday",
  "repo": "frontend",
  "query": "Upgrade web-api source"
}

Determine why the build failed using the buildkite logs.

If any test targets failed, use `get_datadog_tests` to determine which tests failed and why.

Fetch the PR's branch, and check it out with git.

Run tsc for all the projects using:
nx affected -t tsc --parallel 10 --exclude=cms,studio

Fix any errors, commit the changes, and push the branch.

An example of MCP configuration yaml:

description: 
globs: 
alwaysApply: false
mcpTools:
 buildkite:
  - fetch_buildkite_logs
 datadog:
  - get_datadog_tests
 github:
  - search_github_pull_requests