Add .gitignore

.gitignore

@@ -0,0 +1,37 @@
+# Environment
+.env
+.env.local
+.env.production
+
+# Python
+__pycache__/
+*.py[cod]
+*.class
+.Python
+*.so
+venv/
+.venv/
+
+# Node
+node_modules/
+.svelte-kit/
+build/
+dist/
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Logs
+*.log
+logs/
+
+# Data (keep structure, ignore large files)
+# backend/data/*.csv
+# backend/data/*.joblib