feat: [CI] Introduce uv to accelerate pip install (#7127)

### What this PR does / why we need it?
Integrates uv: Significantly accelerates pip install execution and
resolves concurrency issues caused by traditional pip caching
mechanisms.

Why pip install uc-manager is explicitly added:
This project depends on uc-manager. However, installing it via uv pip
install uc-manager currently fails due to a known issue. An issue has
already been filed with the upstream uv repository to address this.
Consequently, we explicitly invoke pip install uc-manager as a temporary
workaround to ensure the build succeeds.
https://github.com/ModelEngine-Group/unified-cache-management/issues/736

Why use UV_SYSTEM_PYTHON: 1:
No virtual environment has been created yet; this configuration has the
same effect as directly using `pip install`.

- vLLM version: v0.16.0
- vLLM main:
15d76f74e2

Signed-off-by: tfhddd <2272751277@qq.com>

.github/workflows/_e2e_nightly_single_node_models.yaml

@@ -67,6 +67,11 @@ jobs:
       env:
         VLLM_USE_MODELSCOPE: True
         GHA_VLLM_ASCEND_VERSION: ${{ inputs.vllm-ascend }}
+        UV_INDEX_URL: http://cache-service.nginx-pypi-cache.svc.cluster.local/pypi/simple
+        UV_EXTRA_INDEX_URL: https://mirrors.huaweicloud.com/ascend/repos/pypi
+        UV_INDEX_STRATEGY: unsafe-best-match
+        UV_NO_CACHE: 1
+        UV_SYSTEM_PYTHON: 1
     steps:
       - name: Check npu and CANN info
         run: |
@@ -91,6 +96,7 @@ jobs:
 
           update-alternatives --install /usr/bin/clang clang /usr/bin/clang-15 20
           update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-15 20
+          pip install uv
 
       - name: Checkout vllm-project/vllm repo
         uses: actions/checkout@v6
@@ -102,14 +108,15 @@ jobs:
       - name: Install vllm-project/vllm from source
         working-directory: ./vllm-empty
         run: |
-          VLLM_TARGET_DEVICE=empty pip install -e .
+          VLLM_TARGET_DEVICE=empty uv pip install -e .
 
       - name: Install vllm-project/vllm-ascend
         env:
           PIP_EXTRA_INDEX_URL: https://mirrors.huaweicloud.com/ascend/repos/pypi
         run: |
-          pip install -r requirements-dev.txt
-          pip install -v -e .
+          pip install uc-manager
+          uv pip install -r requirements-dev.txt
+          uv pip install -v -e .
 
       - name: Install tensorflow (for Molmo-7B-D-0924)
         if: ${{ inputs.runner == 'linux-aarch64-a2b3-1' && contains(inputs.model_list, 'Molmo-7B-D-0924') }}