Cover denied, HEAD (cached/uncached/denied), stale-on-error, circuit-open, and mutable revalidation (304) paths. proxy ~8->58%.
Drives the whole HTTP API against real Postgres/Redis/MinIO + a mock upstream: health, remote CRUD, proxy miss/hit, local upload/download, virtual helm merge, objects, stats, probe. Exercises server + api/v1 + api/v2 + proxy + virtual engines together.