[Misc] Add SPDX-FileCopyrightText (#19100)

Signed-off-by: simon-mo <simon.mo@hey.com>

vllm/engine/async_timeout.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 # Workaround for https://github.com/python/cpython/issues/86296
 #

vllm/engine/llm_engine.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 import copy
 import time

vllm/engine/metrics.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 import time
 from typing import TYPE_CHECKING

vllm/engine/metrics_types.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 """
 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
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 import uuid
 from dataclasses import dataclass, field

vllm/engine/multiprocessing/client.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 import asyncio
 import copy

vllm/engine/multiprocessing/engine.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 import pickle
 import signal

vllm/engine/output_processor/interfaces.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 from abc import ABC, abstractmethod
 from typing import Callable, List

vllm/engine/output_processor/multi_step.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 import functools
 from typing import Callable, List, cast

vllm/engine/output_processor/single_step.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 from typing import List
 

vllm/engine/output_processor/stop_checker.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 from typing import Callable, List, Optional, Tuple
 

vllm/engine/output_processor/util.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 from typing import List
 from typing import Sequence as GenericSequence

vllm/engine/protocol.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 import asyncio
 from abc import ABC, abstractmethod

vllm/entrypoints/api_server.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 """
 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
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 import asyncio
 import json

vllm/entrypoints/cli/benchmark/base.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 import argparse
 
 from vllm.entrypoints.cli.types import CLISubcommand

vllm/entrypoints/cli/benchmark/latency.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 import argparse
 
 from vllm.benchmarks.latency import add_cli_args, main

vllm/entrypoints/cli/benchmark/main.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 import argparse
 
 import vllm.entrypoints.cli.benchmark.latency

vllm/entrypoints/cli/benchmark/serve.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 import argparse
 
 from vllm.benchmarks.serve import add_cli_args, main

vllm/entrypoints/cli/benchmark/throughput.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 import argparse
 
 from vllm.benchmarks.throughput import add_cli_args, main