psql -U postgres with no -d restores into the 'postgres' maintenance
database unless the app DB happens to carry that name. Fourth required
argument passes -d <db-name>; ON_ERROR_STOP=1 so a mid-stream failure
aborts instead of half-restoring silently.
Found by the prod-migration plan final review (finding #6); drilled in
Task 9 before cutover day.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
