[Misc] Add SPDX-License-Identifier headers to python source files (#12628)

- **Add SPDX license headers to python source files**
- **Check for SPDX headers using pre-commit**

commit 9d7ef44c3cfb72ca4c32e1c677d99259d10d4745
Author: Russell Bryant <rbryant@redhat.com>
Date:   Fri Jan 31 14:18:24 2025 -0500

    Add SPDX license headers to python source files
    
This commit adds SPDX license headers to python source files as
recommended to
the project by the Linux Foundation. These headers provide a concise way
that is
both human and machine readable for communicating license information
for each
source file. It helps avoid any ambiguity about the license of the code
and can
    also be easily used by tools to help manage license compliance.
    
The Linux Foundation runs license scans against the codebase to help
ensure
    we are in compliance with the licenses of the code we use, including
dependencies. Having these headers in place helps that tool do its job.
    
    More information can be found on ...

vllm/distributed/utils.py

+# SPDX-License-Identifier: Apache-2.0
+
 # Copyright 2023 The vLLM team.
 # Adapted from
 # https://github.com/NVIDIA/Megatron-LM/blob/main/megatron/core/tensor_parallel/utils.py

vllm/engine/arg_utils.py

+# SPDX-License-Identifier: Apache-2.0
+
 import argparse
 import dataclasses
 import json

vllm/engine/async_llm_engine.py

+# SPDX-License-Identifier: Apache-2.0
+
 import asyncio
 import copy
 import time

vllm/engine/async_timeout.py

+# SPDX-License-Identifier: Apache-2.0
+
 # Workaround for https://github.com/python/cpython/issues/86296
 #
 # From https://github.com/aio-libs/async-timeout/blob/master/async_timeout/__init__.py

vllm/engine/llm_engine.py

+# SPDX-License-Identifier: Apache-2.0
+
 import copy
 import time
 from collections import Counter as collectionsCounter

vllm/engine/metrics.py

+# SPDX-License-Identifier: Apache-2.0
+
 import time
 from typing import TYPE_CHECKING
 from typing import Counter as CollectionsCounter

vllm/engine/metrics_types.py

+# SPDX-License-Identifier: Apache-2.0
 """
 These types are defined in this file to avoid importing vllm.engine.metrics
 and therefore importing prometheus_client.

vllm/engine/multiprocessing/__init__.py

+# SPDX-License-Identifier: Apache-2.0
+
 import uuid
 from dataclasses import dataclass, field
 from enum import Enum

vllm/engine/multiprocessing/client.py

+# SPDX-License-Identifier: Apache-2.0
+
 import asyncio
 import copy
 import pickle

vllm/engine/multiprocessing/engine.py

+# SPDX-License-Identifier: Apache-2.0
+
 import pickle
 import signal
 from contextlib import contextmanager

vllm/engine/output_processor/interfaces.py

+# SPDX-License-Identifier: Apache-2.0
+
 from abc import ABC, abstractmethod
 from typing import Callable, List
 

vllm/engine/output_processor/multi_step.py

+# SPDX-License-Identifier: Apache-2.0
+
 import functools
 from typing import Callable, List, cast
 

vllm/engine/output_processor/single_step.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import List
 
 from vllm.config import SchedulerConfig

vllm/engine/output_processor/stop_checker.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import Callable, List, Optional, Tuple
 
 from vllm.lora.request import LoRARequest

vllm/engine/output_processor/util.py

+# SPDX-License-Identifier: Apache-2.0
+
 from typing import List
 from typing import Sequence as GenericSequence
 from typing import cast

vllm/engine/protocol.py

+# SPDX-License-Identifier: Apache-2.0
+
 import asyncio
 from abc import ABC, abstractmethod
 from typing import AsyncGenerator, List, Mapping, Optional

vllm/entrypoints/api_server.py

+# SPDX-License-Identifier: Apache-2.0
 """
 NOTE: This API server is used only for demonstrating usage of AsyncEngine
 and simple performance benchmarks. It is not intended for production use.

vllm/entrypoints/chat_utils.py

+# SPDX-License-Identifier: Apache-2.0
+
 import asyncio
 import codecs
 import json

vllm/entrypoints/launcher.py

+# SPDX-License-Identifier: Apache-2.0
+
 import asyncio
 import signal
 from http import HTTPStatus

vllm/entrypoints/llm.py

+# SPDX-License-Identifier: Apache-2.0
+
 import itertools
 import warnings
 from contextlib import contextmanager