chore: Add .gitignore to prevent accidental commit of sensitive files

Add standard Python .gitignore covering bytecode, build artifacts,
virtual environments, IDE files, test caches, and environment
variable files (.env) that may contain secrets.

Author: itinance

.gitignore

@@ -1,8 +1,35 @@
+# Byte-compiled / optimized / DLL files
 __pycache__/
-*.pyc
-*.egg-info/
+*.py[cod]
+*$py.class
+
+# Distribution / packaging
 dist/
 build/
-.eggs/
+*.egg-info/
 *.egg
+.eggs/
+
+# Virtual environments
+.venv/
+venv/
+env/
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+
+# Testing
 .pytest_cache/
+.coverage
+htmlcov/
+
+# Environment variables
+.env
+.env.local
+
+# OS
+.DS_Store
+Thumbs.db