chore: satisfy changed-file policy

Scoped pre-commit over the 27 files this rebase touches: ruff format
reflow, the vLLM-Omni SPDX copyright line on the new modules, and wording
the typos hook rejected.

The Python 3.10 mypy hook still reports 24 errors across five of these
files. All 24 sit on pre-existing lines; none fall on a line this rebase
changed, which the repository documents as the CI-skipped condition.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0146Xu5Sgj4vXxLxvLjV5YPj
Signed-off-by: tzhouam <tzhouam@connect.ust.hk>

tests/diffusion/diffusion_kv/test_spec_discovery.py

@@ -11,11 +11,11 @@ from torch import nn
 from vllm.v1.kv_cache_interface import FullAttentionSpec, KVCacheConfig, KVCacheGroupSpec
 
 import vllm_omni.diffusion.worker.diffusion_worker as diffusion_worker_module
+from tests.helpers.kv_layout import build_kv_cache_tensor, layout_for_backend
 from vllm_omni.diffusion.attention.layer import Attention
 from vllm_omni.diffusion.diffusion_kv.config import DiffusionKVCacheMode
 from vllm_omni.diffusion.worker.diffusion_model_runner import DiffusionModelRunner
 from vllm_omni.diffusion.worker.diffusion_worker import DiffusionWorker
-from tests.helpers.kv_layout import build_kv_cache_tensor, layout_for_backend
 
 pytestmark = [pytest.mark.core_model, pytest.mark.cpu, pytest.mark.diffusion]