v5.0.0

Every service now answers GET /ops/overview with its own health, the lag of each of its listener groups, the dead letter depth per topic, the state of every circuit breaker and, on the order service, the sagas that are still open and the ones that have already missed a deadline. The numbers come from the gauges the Prometheus endpoint already publishes, so the page an operator reads and the dashboards cannot disagree, and ledgermesh.saga.stuck is published alongside them. The chaos harness gained a tight profile that doubles the kills and restarts the victim after two seconds instead of five, reachable as make chaos-tight, and its summary now ends with the overview of all three services. The recorded run in the README is a real make chaos on this release: 1200 orders at 20 a second, three kills, 1162 confirmed, 38 cancelled for stock, none failed or stuck, with no lag, no dead letters and no stuck orders left behind. Host port overrides let the stack run beside something else already on 8081 to 8083.