CloudArc bounded-memory benchmark

Make CloudArc large-package performance reproducible, measurable and safe to ship. Drives the bounded-memory workflow for the .vibo container - streaming pack/unpack inside a fixed RSS ceiling, high-cardinality multi-file archives with SHA-256 dedup, remote-search range telemetry and the CI/manual gates that guard them. Use when changing benchmarks, SLOs, manifest or index cardinality, remote metadata reads or GitHub Actions checks, or when reviewing a large-package MVP before real cloud providers are switched on.