chore: ignore local data directory and temp artifacts to avoid committing large files

.gitignore

@@ -5,3 +5,12 @@ results/**/plots/*.png
 
 # Ignore large results directories (data now tracked with LFS)
 results/**
+
+# Do not commit local datasets or experiment outputs
+data/
+
+# Ignore local temp/cache artifacts
+*.parquet
+*.tmp
+*.log
+.DS_Store