The stable gate proved Validate and Full Performance on the exact SHA but
never ran the release in Home Assistant itself. houseplan-e2e installs
the release's houseplan.zip — the bytes HACS ships — into HA in docker
and walks the sidebar page, dashboards, roles, PDF, restart and the
stable→tag upgrade. release.yml now dispatches e2e.yml on the tag for
`!prerelease` releases and waits for it (scripts/e2e-gate.mjs, modelled
on validate-gate.mjs): the gate recognises its own run by `HP <tag>` in
the job names, ignores foreign dispatches, and reports red / missing /
cancelled / token error with the run link. Betas are untouched.
Mutants: release-ships-on-red-e2e, release-trusts-foreign-e2e-run.
Issue: #514
User-Visible: no
