- Fix has_unique flag reading from field definition (was scanning fragment fields)
- Implement duplicate validation in CLI and TUI backends
- Add item counter update in Web backend after add/delete operations
- Refactor Web JavaScript: remove global constants, use closure-based state per group
- Store repeating group config in data-* attributes instead of global variables
- Update documentation and examples with unique = true attribute
- All backends now enforce unique items validation consistently
