Backend:
- Tree usage_count: use SQL-level UPDATE (Tree.usage_count + 1) instead
of Python-level increment to prevent lost updates under concurrency
- Tag usage_count: same SQL-level atomic increment/decrement in both
create_tree and update_tree (delete_tree already used this pattern)
- Plan tree limit: re-check count after db.flush() to close the TOCTOU
window where two concurrent creates could both pass the pre-check
Frontend:
- TreeEditorPage: add isSaving early-return guard inside handleSaveDraft
and handlePublish callbacks so Ctrl+S can't bypass the button disabled
prop and fire duplicate save requests
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
7e3b383a65