[Misc] Add SPDX-FileCopyrightText (#20428)

Signed-off-by: Jee Jee Li <pandaleefree@gmail.com>

benchmarks/kernels/bench_fp8_gemm.py

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

examples/offline_inference/spec_decode.py

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

examples/online_serving/disaggregated_serving_p2p_nccl_xpyd/disagg_proxy_p2p_nccl_xpyd.py

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

examples/online_serving/multi_instance_data_parallel.py

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

examples/online_serving/openai_chat_completion_client_with_tools_xlam.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 # ruff: noqa: E501
 """
 Set up this example by starting a vLLM OpenAI-compatible server with tool call

examples/online_serving/openai_chat_completion_client_with_tools_xlam_streaming.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 # ruff: noqa: E501
 """
 Set up this example by starting a vLLM OpenAI-compatible server with tool call

tests/compile/test_fusion_attn.py

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

tests/kernels/moe/parallel_utils.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 """
 DeepEP test utilities
 """

tests/kernels/moe/test_deepep_deepgemm_moe.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 """
 Test DeepEP + DeepGEMM integration
 DeepGEMM are gemm kernels specialized for the

tests/kernels/moe/test_deepep_moe.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 """
 Test deepep dispatch-combine logic
 """

tests/kernels/moe/test_deepgemm.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 """
 Unit-test DeepGEMM FP8 kernels (no DeepEP).
 Compare DeepGEMM path against the Triton fallback inside vLLM's fused_experts.

tests/kernels/test_apply_repetition_penalties.py

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

tests/kernels/test_flex_attention.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 """Integration tests for FlexAttention backend vs default backend"""
 
 import random

tests/models/language/pooling/test_intfloat.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 import pytest
 
 from ...utils import EmbedModelInfo

tests/quantization/test_rtn.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 # Copyright © 2025, Oracle and/or its affiliates.
 """Tests RTN quantization startup and generation, 
 doesn't test correctness

tests/tool_use/test_minimax_tool_parser.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 # ruff: noqa: E501
 
 import json

tests/tool_use/test_xlam_tool_parser.py

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

tests/v1/sample/test_logits_processors.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
 import random
 from collections.abc import Callable

tests/v1/test_request.py

 # SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 from vllm.v1.request import RequestStatus
 
 

tests/v1/tpu/test_spmd_model_weight_loading.py

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