MCP Server - instrumentation spec document

<br>[https://github.com/open-telemetry/semantic-conventions/pull/2083#issuecomment-2993946311](https://github.com/open-telemetry/semantic-conventions/pull/2083#issuecomment-2993946311)<br>

Our MCP server monitoring doc is a good starting point: [https://github.com/getsentry/sentry-mcp/blob/main/docs/monitoring.mdc](https://github.com/getsentry/sentry-mcp/blob/main/docs/monitoring.mdc)