Add initial implementation of Matrix chat widget with Flask blueprint

- Create .gitignore to exclude Python-related files
- Implement chat blueprint in __init__.py
- Add chat HTML template with input and message display
- Create CSS for chat styling
- Develop JavaScript for chat functionality and Matrix API integration
- Configure pyproject.toml for project metadata and dependencies

.gitignore

@@ -0,0 +1,6 @@
+__pycache__/
+*.py[cod]
+*.egg-info/
+dist/
+build/
+.venv/