Review call: 46 lines of documentation around a single constant, part of
it already stale. The worst paragraph explained why the earlier per-hive
shape had been justified wrongly — history of a design that never
shipped, written into the file within an hour of that design being
dropped. A file is not a changelog; why it was wrong belongs in the PR.
The constant moves to lib.rs beside the status bucket name, keeping only
the rationale that stays true: three crates must agree on the string, and
the one that agrees hardest speaks neither jetstream nor kv, which is why
it cannot sit behind a feature gate.
status earns a module of its own because it holds a bucket name AND the
functions that open it. This held a constant.