Store Beat Saber backups in adjacent repo

src/plugin_helper/cli.py

@@ -238,11 +238,11 @@ def build_parser() -> argparse.ArgumentParser:
 
     backup = subcommands.add_parser(
         "backup-userdata",
-        help="Copy UserData and Windows AppData into this repo",
+        help="Copy UserData and Windows AppData into the adjacent backups repo",
         parents=[_common_parent()],
     )
     backup.add_argument("--instance", required=True)
-    backup.add_argument("--backup-root", default="backups/beat-saber", help="Repo-local backup directory")
+    backup.add_argument("--backup-root", default="../backups/beat-saber", help="Backup directory")
     backup.add_argument("--appdata-path", help="Override Beat Saber Windows AppData path")
     backup.add_argument("--no-appdata", action="store_true", help="Only copy UserData")
 
@@ -560,7 +560,7 @@ def run(argv: list[str] | None = None) -> int:
             root = repo_root()
             backup_root = Path(args.backup_root).expanduser()
             if not backup_root.is_absolute():
-                backup_root = root / backup_root
+                backup_root = (root / backup_root).resolve()
             result = sync_windows_data_repo(
                 instance=args.instance,
                 instance_path=instance.path,