Make static methods in Error final

[Nyholm]

Motivation and Context

This will just make the API more strict. It allows us add parameters to these methods without breaking BC.

How Has This Been Tested?

I did not test it

Breaking Changes

Yes, this is a breaking change and should be merged when preparing for 0.3.0

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

[chr-hertel]

Thanks!