Update OTel GenAI Conventions

Analyze OpenTelemetry GenAI semantic-conventions changes — PRs, changelog snapshots, date ranges, or releases — primarily from open-telemetry/semantic-conventions-genai, and produce compensating updates in dotnet/extensions. See the Migration Note below for context, including where these conventions were previously managed.

Migration Note

The OpenTelemetry GenAI semantic conventions are maintained in a dedicated repo: open-telemetry/semantic-conventions-genai, which also hosts mcp, openai, anthropic, aws-bedrock, and azure-ai-inference conventions. They were previously managed in the consolidated open-telemetry/semantic-conventions repo under the area:gen-ai label.

Implications for this skill: