Initial commit: Python library for Markdown note services

- Add MDAuth class for authentication and session management
- Add MDClient class for note operations (CRUD + export/search)
- Add CLI tool mdclient_cli.py for quick operations
- Support for CodiMD, HedgeDoc, and HackMD services
- Multi-endpoint API compatibility

Co-Authored-By: Claude Sonnet 4 <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,31 @@
+# Environment and credentials
+.env
+key.conf
+
+# Python
+__pycache__/
+*.py[cod]
+*$py.class
+*.so
+.Python
+
+# Virtual environments
+venv/
+env/
+ENV/
+
+# Build artifacts
+mdclient.egg-info/
+dist/
+build/
+*.egg
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+
+# OS
+.DS_Store
+Thumbs.db