- Call sync_steps_from_tree in update_tree whenever the tree is published
(status transitions to 'published' or is already published and structure changes)
- Call deactivate_synced_steps_for_tree in delete_tree before db.commit()
so the FK SET NULL does not nullify source_tree_id before the WHERE clause runs
- Fix ::jsonb cast syntax in step_sync.py (asyncpg rejects :: operator in text()
queries; replaced with CAST(:content AS jsonb))
- Add UniqueConstraint('source_tree_id','source_node_id') to StepLibrary model
so Base.metadata.create_all (used by tests) creates the constraint that the
ON CONFLICT clause in sync_steps_from_tree depends on
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>