Add YAPF style + ignore, and format tracked Python files

scripts/format_tracked.py

@@ -0,0 +1,26 @@
+#!/usr/bin/env python3
+"""Format all tracked Python files using the repo's YAPF style.
+
+This script intentionally formats only files tracked by git to avoid touching
+files that are ignored (e.g., venv, site-packages).
+"""
+import subprocess
+import sys
+
+try:
+    out = subprocess.check_output(["git", "ls-files", "*.py"]).decode("utf-8")
+except subprocess.CalledProcessError as exc:
+    print("Failed to get tracked files from git:", exc, file=sys.stderr)
+    sys.exit(1)
+
+files = [f for f in (line.strip() for line in out.splitlines()) if f]
+print(f"Formatting {len(files)} tracked python files...")
+if not files:
+    print("No tracked python files found.")
+    sys.exit(0)
+
+for path in files:
+    print(path)
+    subprocess.run([sys.executable, "-m", "yapf", "-i", "--style", ".style.yapf", path], check=False)
+
+print("Done")