Correlation Tracing

This implements correlation IDs and distributed tracing across microservices so you can follow requests through your system. You get Express middleware that generates or extracts trace IDs, AsyncLocalStorage for context propagation, and integration patterns for OpenTelemetry. The skill includes Python implementations too, not just Node. Use it when you're debugging why requests are slow or failing in a distributed system and you need to see the full path. The practical bit is the structured logging integration, so your correlation IDs actually show up where you need them. Just watch your sampling rates in production or you'll drown in trace data.