Add .gitignore to exclude cache, venv, and local files

.gitignore

@@ -0,0 +1,24 @@
+# Python bytecode / cache
+__pycache__/
+*.py[cod]
+*.so
+
+# Virtual environment
+venv/
+
+# Local Unix domain sockets
+*.sock
+
+# Environment & config files (if local only)
+*.env
+*.local.json
+system_info.json
+site_info.json
+frontend_config.json
+
+# Logs
+*.log
+
+# OS-specific
+.DS_Store
+Thumbs.db