The only production consumer of the UpdaterRegistry is the plan endpoint
(GET /api/updates/plan); every real apply runs through the in-Go pipeline
in manager.go ApplyUpdate, with concurrency held by updateMu/updateInFlight.
The InstallShAdapter Execute/Rollback path (install.sh piping, rollback
binary download, health wait) and the UpdateQueue were never called outside
tests, so fixes made there silently did nothing. Adapters are now plan
providers only: the Updater interface keeps SupportsApply, PrepareUpdate,
and GetDeploymentType, pinned by the new registry proof in
internal/api/updates_test.go.
The orphaned fetchAndVerifyReleaseSignature helper goes with it; its
fail-closed sidecar tests now exercise the manager's
downloadAndVerifyReleaseSignature directly. The deployment-installability
sshsig invariant now names the manager pipeline as the only surface that
fetches release artifacts, and api-contracts, storage-recovery, and
agent-lifecycle pin the same plan-provider-only shape at their update
transport boundaries. Stale adapter references in build-release.sh,
validate-release.sh, and the installtests comments are updated to match.
rcourtman
33d318a29e