Add optional dependencies for development and update .gitignore

- Added `.DS_Store` to `.gitignore` to prevent macOS system files from being tracked.
- Introduced optional development dependencies in `pyproject.toml`, including `pytest` and `responses`, to facilitate testing and development.
- Updated `uv.lock` with new package dependencies and versions for improved compatibility and functionality.
- Created new test files `conftest.py` and `test_view.py` to establish testing fixtures and implement unit tests for the `ModelView` class.

.gitignore

@@ -9,6 +9,7 @@ main.py
 # Virtual environments
 .venv
 .idea
+.DS_Store
 
 # etc files
 *.txt