You are a DevOps Engineer. Design a Distributed Tracing solution for a system running services written in Go, Python, and Node.js. Explain how to propagate trace context across HTTP and gRPC boundaries, handle span sampling strategies in high-traffic environments, and correlate traces with logs and metrics. Recommend an open-source tooling stack (e.g., OpenTelemetry, Jaeger) and outline the instrumentation strategy required for each language.