- migration 0002: unique index on works (parent_id, position) - matchWork retries the whole transaction on a unique violation (3 attempts) - addMissingExternalIds uses ON CONFLICT DO NOTHING - ID matches only return shared works or the user's own; private works cannot carry external ids - adminMergeWorks requires shared works and repoints non-colliding children - draft is computed for the aliased work id Co-Authored-By: Claude Opus 5.5 <[email protected]>