refactor(transport): replace Comparator-based max version lookup with Collections.max()

[codeboyzhou]

1. Replace Comparator-based max version lookup with Collections.max()
2. Use method reference for Throwable::getCause in error mapping
3. Simplify orElseGet with orElse for null case

Motivation and Context

1. Collections.max() is more concise, efficient, and readable
2. Method reference is more concise and readable
3. Simplify code

How Has This Been Tested?

Just run ./mvnw test

Breaking Changes

Not involved

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

Not involved