Fix books list command NameError (_log).

EOF

Co-authored-by: Cursor <cursoragent@cursor.com>

src/gpu_rent/books.py

@@ -441,7 +441,7 @@ def main(argv: list[str] | None = None) -> int:
         elif args.cmd == "list":
             for bid in iter_installed_books(out):
                 meta = read_meta(bid, out) or {}
-                log(
+                _log(
                     f"{bid}: rows={meta.get('row_count', '?')} "
                     f"sha={str(meta.get('content_sha', ''))[:12]}"
                 )