Three cleanups from `/simplify` review:
- Promote `archived_rejection_message` and `ensure_not_archived` to `pub`
via operations/mod.rs and reuse them from `resume`, the CLI rewind
caller, and the server's `reject_if_archived` guard so the canonical
error string lives in exactly one place.
- Tighten `RewindInput.current_status` from `Option<RunStatus>` to
`RunStatus`. The runtime check for None was enforcing a compile-time
invariant. CLI callers already load the projection and now surface a
clean error up-front if it's missing. Drop the None-branch test that
existed only to cover the removed runtime check.
- Collapse `archive_run` / `unarchive_run` HTTP handlers into a shared
`run_archive_action` body with an `ArchiveAction` enum, mirroring the
CLI pattern. Removes ~20 lines of copy-paste and unifies error-mapping.
Also drop narrative comments that referenced plan unit numbers in the
scenario tests, and clean up the convoluted `ps_runs` helper pattern
that built an empty-slot arg vec before filling it in.
No behavior change. Full workspace: 4185 tests pass, clippy clean.
Single #[test] that exercises the full CLI archive flow: run a dry-run to
succeeded, verify ps -a shows it, archive, verify default ps hides it and
ps -a shows archived, unarchive, verify the prior terminal status is
restored, then re-archive and rm to confirm archived runs remain
delete-able (plan Scope Boundaries).
