Migrate to vitest from jest

[mattzcarey]

its newer, faster, works natively with the modern toolchain like typescript.

Motivation and Context

How Has This Been Tested?

Breaking Changes

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

[mattzcarey]

The main motivation to do this is that vitest works with ESM modules natively. This means we can use MSW to test MCP servers more effectively. MSW is a lovely tool and is pretty much standard practise when testing typescript servers.