- Implemented robust undo system supporting coalescing of text operations (insert, backspace, delete).
- Added `UndoSystem` integration into the editor/commands pipeline.
- Wrote extensive unit tests for various undo/redo scenarios, including multiline operations, cursor preservation, and history management.
- Refactored to ensure consistent cursor behavior during undo/redo actions.
- Updated CMake to include new tests.
- Introduced visual-line mode for multi-line selection and edits.
- Implemented commands, rendering, and keyboard shortcuts.
- Added tests for broadcast operations in visual-line mode.
