style: apply ruff + ruff-format fixes flagged by pre-commit.ci

Both fixes are pure formatter output:
- get_started/blender_demo.py: drop stray blank line inside import block
- tests/test_libero_base_empty_traj.py: PEP-8 blank lines around nested
  def / monkeypatch.setattr lines

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: geng-haoran

get_started/blender_demo.py

@@ -59,7 +59,6 @@
 from metasim.utils.hf_util import check_and_download_recursive
 from metasim.utils.obs_utils import ObsSaver
 from metasim.utils.setup_util import get_handler
-
 from roboverse_pack.blender.asset_paths import get_hdri_dir, get_material_library
 
 

tests/test_libero_base_empty_traj.py

@@ -105,9 +105,11 @@ def _checker_reset(*a, **k):
 
     # Patch super().reset to record ordering.
     from metasim.task.base import BaseTaskEnv
+
     def _super_reset(self, states=None, env_ids=None):
         order.append("super")
         return "sentinel"
+
     monkeypatch.setattr(BaseTaskEnv, "reset", _super_reset)
 
     result = task.reset(env_ids=[0])
@@ -123,6 +125,7 @@ def test_reset_tolerates_missing_checker(monkeypatch):
     task.checker = None
 
     from metasim.task.base import BaseTaskEnv
+
     monkeypatch.setattr(BaseTaskEnv, "reset", lambda self, states=None, env_ids=None: "ok")
 
     assert task.reset(env_ids=[0]) == "ok"