The on-page label for `--release alpha|beta` cuts used to read
`vX.Y.Z-channel · YYYY-MM-DD · word-word-word`. The three-word slug
(derived deterministically from the source SHA via shared/build-words.txt)
was meant to make "is this the same build you emailed about?" a glance
check, but the cute-words layer turned out to be more confusing than
clarifying — testers prefer a real timestamp + short SHA.
New label shape, identical to plain dev builds:
vX.Y.Z-channel · YYYY-MM-DD HH:MM:SS · <short-source-sha>[-dirty]
Helper renamed from _source_commit_slug to _source_commit_short_sha,
returning the short SHA of the source commit (walking past any
`chore(embedded): cut …` commit at HEAD so a re-cut on unchanged
source produces the same SHA). The wordlist file is no longer
referenced and is removed; tests/build-label.spec.js's regex
simplified to require the full timestamp + SHA form.