OpenTelemetry inject trace context propagation in _meta

[aabmass]

Part of #421

Motivation and Context

This implements OpenTelemetry context forward propagation (if available) through _meta, as specified in

• SEP414 SEP-414: Document OpenTelemetry Trace Context Propagation Conventions modelcontextprotocol#414
• OpenTelemetry semantic conventions https://github.com/open-telemetry/semantic-conventions/blob/v1.39.0/docs/gen-ai/mcp.md

MCP C# SDK has a similar implementation: https://github.com/modelcontextprotocol/csharp-sdk/blob/v0.8.0-preview.1/src/ModelContextProtocol.Core/Diagnostics.cs#L64. This is working for normal client to server calls, and for server calls back to the client like MCP Sampling.

How Has This Been Tested?

Added new test cases

Breaking Changes

No

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

Extracting the context from _meta into OTel context in the receiving side is the next PR (#2133), but depends on merging #1996

[maxisbey]

Thanks for the PR. This has since landed via #2381. Closing as part of a general backlog cleanup following the v2 release. If this is still relevant against v2, feel free to reopen.

_{AI Disclaimer}