Bump pkce up to 5.0.0 to fix CJS dependency issue

[heyitsaamir]

This is to fix #217. This library wasn't working in CommonJS projects because pkce didn't export a commonjs version. In 5.0.0, they fixed this issue via crouchcd/pkce-challenge#33. In this PR, we are simply bumping the version to incorporate the fix.

The PKCE package was now exporting index.node.d.ts (for some reason), so I made a change in our tsconfig to resolve that correctly.

Motivation and Context

Without this, we weren't able to use this library in CJS projects. See issue mentioned above.

How Has This Been Tested?

Tested basic stuff locally, but not auth. Can someone who has auth stuff set up test that?

Breaking Changes

Don't think so. Unit tests pass but admittedly I have not tested the auth scenario.

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

[heyitsaamir]

Apologies for the tag, but any chance we could prioritize this? CJS is broken without this.

@cliffhall / @allenzhou101