* chore(release): retire the Tideclaw alpha release track
Tideclaw alpha/nightly publication is retired. Alpha remains readable as
history (existing v*-alpha tags, published versions, changelog and
upgrade-survivor baselines, product version ordering), but it can no longer
authorize a release.
Every active release boundary now rejects an alpha version or -alpha.N tag,
the alpha npm dist-tag, and tideclaw/alpha/* workflow or tooling routes:
preparation, Full Release Validation publication selection, npm preflight,
approval receipts, core/plugin npm and ClawHub publication, native handoffs,
and finalization. Channel mappings throw for alpha instead of falling through
to latest. The Tideclaw branch routes, alpha dist-tag options, the alpha FRV
publication route, and the alpha-only Docker runtime-assets job are removed.
Beta, stable, extended-stable, and correction releases are unchanged.
The release-openclaw-nightly skill is deleted and the release skills and docs
no longer describe the alpha track.
* test(release): drop retired alpha preparation and finalization expectations
* test(release): drop remaining retired alpha references
