design: add design for rate limiting

[samthanawalla]

I added an example for how rate limiting should be implemented using middleware.

Fixes #22

Motivation and Context

Rate limiting can be enabled using middleware. This adds an example on how to do that.

How Has This Been Tested?

N/A

Breaking Changes

No

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

Additional context

[findleyr]

I think the section on rate limiting should be brief, suggesting that it be implemented with middleware. Can you instead promote your example to a fully fledged example in the examples/ directory? Then it will be discoverable.

[samthanawalla]

Sounds good. I added examples/rate-limiting.
For the per session rate limiting, we will need a way to expose a session ID but we can discuss later.