Problems

1. Sync step never auto-merges (cascade stalls).
gh pr merge --auto --merge fails with Pull request is in clean status (enablePullRequestAutoMerge) because main has no required status checks, so a fresh cascade PR is immediately mergeable and GitHub refuses to enable auto-merge on an already-clean PR. The step exits 1, the sync PR is left open (hit on runs for #53 and #57).

2. Release notes / CHANGELOG carry no domain diff.
The cut step writes a generic PSL data: bump structured-public-domains to vX message. The actual added/removed domain list (already present in the upstream structured-public-domains release body) is not propagated, so the email release does not say which domains changed.

Fix (psl-cascade.yml)

1. Robust merge: gh pr merge --merge "$BRANCH" || gh pr merge --auto --merge "$BRANCH" (immediate merge when clean — the bot bypasses branch protection; fall back to auto when checks are pending).
2. Cut step fetches the upstream structured-public-domains release body (gh release view vVERSION --repo .../structured-public-domains) and embeds the domain diff in the email CHANGELOG entry + GitHub release notes.

Acceptance

• A dispatched cascade run lands the sync on main with no manual merge
• The email data release notes + CHANGELOG list the added/removed domains

Estimate

1h