- Added `text_model` class to manage text content and selection state, supporting UTF-32 storage for accurate character-level operations.
- Implemented UTF-8 to UTF-32 conversion functions for seamless text input.
- Introduced `text_selection` class to represent selection ranges using anchor/focus model.
- Added methods for text insertion, deletion, and selection management, including word boundary detection.
- Implemented maximum length constraints for text input.
- Provided callback mechanism for text change notifications.