Observability signal correlation

Design the correlation layer of a unified observability platform that ties together the three signals, metrics, logs, and traces, so that from a spike on a latency metric an engineer can jump to the exact traces behind that spike and the logs for those traces, in seconds. The three signals live in three different stores with different data models and retention. Design the linking model, the query flow, and how you keep correlation cheap and reliable without forcing all three into one store.