- Added `test_reflow_indented_bullets.cc` to verify correct reflow handling for indented bullet points.
- Enhanced undo system with additional tests for cursor adjacency, explicit grouping, branching, newline independence, and dirty-state tracking.
- Introduced external modification detection for files and required confirmation before overwrites.
- Refactored buffer save logic to use atomic writes and track on-disk identity.
- Updated CMake to include new test files and bumped version to 1.6.4.
- Added branching model for undo/redo, enabling multiple redo paths and branch selection.
- Updated `UndoNode` to include `parent` and refined hierarchical navigation.
- Extended `UndoSystem` with branching logic for redo operations, supporting sibling branch selection.
- Overhauled tests to validate branching behavior and tree invariants.
- Refined editor command logic for undo/redo with repeat counts and branch selection.
- Enabled test-only introspection hooks for undo tree validation.
- Updated CMake to include test definitions (`KTE_TESTS` flag).
- 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.
