Add .gitignore to protect secrets and local data"

.gitignore

@@ -0,0 +1,39 @@
+# Secrets
+.env
+*.env.local
+
+# Python
+__pycache__/
+*.pyc
+*.pyo
+*.egg-info/
+dist/
+build/
+.venv/
+venv/
+
+# uv
+.python-version
+
+# Data (large files — keep local)
+data/*.parquet
+data/chroma/
+data/papers/
+
+# Factor store (your alpha history — keep private)
+factor_store/*.duckdb
+factor_store/*.duckdb.wal
+
+# Logs
+logs/
+*.log
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+
+# OS
+.DS_Store
+Thumbs.db