doc: Add example of testing against TS SDK

[nbarbettini]

The CONTRIBUTING.md doc says new scenarios must be tested against a real SDK, but doesn't show an example of doing this. Reformatted the examples section and added a quick example of testing against the latest TS SDK.

Motivation and Context

Clearer instructions for a new contributor.

How Has This Been Tested?

I put myself in the shoes of a new contributor. 🙂

Breaking Changes

None

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

[pkg-pr-new]

Open in StackBlitz

npx https://pkg.pr.new/@modelcontextprotocol/conformance@237

commit: 3e7c9cc

[pcarleton]

thanks for this!

might be worth us adding some shell scripts to make this super easy. e.g. even make it easy to run at different git commits / branches, since often the passing scenario impl is still on a branch