fix(release): verify published tags after the staging cleanup

[rmyndharis]

verify-published is the check that catches a release tag that is missing or points at the wrong digest, and the comment above it names the incident it exists for. It only needed docker and promote, so it could run beside cleanup-staging rather than after it. That cleanup deletes the package version when it reads only the staging tag on it, and GHCR's package-versions API is eventually consistent, so the deletion this check guards against could happen after the check had already passed.

• verify-published now also needs cleanup-staging, and runs whenever promote succeeded, so a best-effort cleanup failure cannot suppress it.
• The sessions table importer skips a row whose id is not a safe path key, the same way it already skips an unsafe name: the id now names the on-disk auth directory, so an unvalidated one would surface later as a refused start instead of a skipped row with a reason.
• Two engine-interface comments still described the credential-teardown removal as targeting the session name's directory; they now say the directory is keyed by the id while the fence stays keyed by the unique name.

Verification: actionlint is clean, the new importer spec fails without the id guard, and lint, tsc --noEmit, format:check, test:cov (6382 tests) and test:docs pass locally.