Read per-subsystem availability and dataset freshness

Reports each subsystem independently, the OSM dataset timestamp, minute-diff replication state and lag in seconds, whether machine payment can settle, the deployed Overpass engine version, and for every dataset the engine build serving it and the data snapshot it answers from. overpass.displayVersion is read from the running engine binary (for example "0.7.62.11 87bfad18") and changes automatically when production is upgraded.

When to use: Monitor service availability, dataset freshness, payment settlement readiness, and the engine and dataset versions behind each answer.

When not to use: Poll at an appropriate interval; status checks are not required before every API call.