Block-Editor Ordering, Collaboration, and Keyboard Contracts
General patterns: fractional ordering, optimistic rebase, IME defer, keyboard undo delegation, scoped popover, Jest ESM shim, and more
- For sibling ordering, a fractional position key + neighbor anchor + tie-break is better for concurrent inserts than an integer index.
- Optimistic UI can't rebase without an inverse patch, and the remote seq must be the merge authority.