[Rebase] Rebase to vLLM 0.29.0 (#7230)

Signed-off-by: tzhouam <tzhouam@connect.ust.hk>
Signed-off-by: Zhou Taichang <tzhouam@connect.ust.hk>
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

tests/entrypoints/openai_api/test_modality_validation.py

@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
 """Regression tests for output modality validation in chat completions.
 
 Covers:
@@ -13,7 +14,7 @@ from unittest.mock import AsyncMock, MagicMock, patch
 
 import pytest
 from vllm.entrypoints.openai.chat_completion.protocol import ChatCompletionRequest
-from vllm.entrypoints.openai.engine.protocol import ErrorResponse
+from vllm.entrypoints.serve.engine.protocol import ErrorResponse
 
 pytestmark = [pytest.mark.core_model, pytest.mark.cpu]