This adds _meta on additional resource types throughout the specification, specifically those that appear as arrays in list results or multi-part content.

Motivation and Context

See discussion for motivation.

How Has This Been Tested?

Since this change merely adds additional optional inert metadata, it should be a safe non-breaking change for all existing clients and servers.

Breaking Changes

NONE

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