Add Linux CI pipeline for WebGPU (microsoft#25219)

### Description

Currently only build is enabled. Testing step is failing because of
error like this:

```
1: /onnxruntime_src/onnxruntime/core/providers/webgpu/webgpu_context.cc:87 onnxruntime::webgpu::WebGpuContext::Initialize(const onnxruntime::webgpu::WebGpuBufferCacheConfig&, int, bool)::<lambda()>::<lambda(wgpu::RequestAdapterStatus, wgpu::Adapter, wgpu::StringView, wgpu::Adapter*)> status == wgpu::RequestAdapterStatus::Success was false. Failed to get a WebGPU adapter: No supported adapters
1: 
```

Author: fs-eire

.github/workflows/linux_webgpu.yml

@@ -0,0 +1,101 @@
+name: Linux WebGPU CI
+
+on:
+  push:
+    branches: [main, 'rel-*']
+  pull_request:
+    branches: [main, 'rel-*']
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.event_name == 'pull_request' && github.ref || github.sha }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+  packages: write
+  attestations: write
+  id-token: write
+
+jobs:
+  build-linux-webgpu-x64-release:
+    name: Build Linux WebGPU x64 Release
+    # This job runs on a CPU node using the reusable build workflow
+    uses: ./.github/workflows/reusable_linux_build.yml
+    with:
+      pool_name: "onnxruntime-github-Ubuntu2204-AMD-CPU" # Build pool
+      build_config: Release
+      architecture: x64
+      dockerfile_path: tools/ci_build/github/linux/docker/Dockerfile.manylinux2_28_webgpu
+      docker_image_repo: onnxruntimecpubuildpythonx64
+      extra_build_flags: '--use_binskim_compliant_compile_flags --build_wheel --use_webgpu --build_java --cmake_extra_defines onnxruntime_BUILD_UNIT_TESTS=ON'
+      python_path_prefix: 'PATH=/opt/python/cp310-cp310/bin:$PATH'
+      run_tests: false
+      upload_build_output: true
+      execution_providers: 'webgpu'
+    secrets:
+      GH_TOKEN: ${{ secrets.GITHUB_TOKEN }} # Pass token for reusable workflow needs (e.g., docker build action)
+
+  # TODO: the following test step is currently failing. Need to fix and re-enable it
+
+  # test-linux-webgpu-x64-release:
+  #   name: Test Linux WebGPU x64 Release
+  #   needs: build-linux-webgpu-x64-release
+  #   runs-on:
+  #     - self-hosted
+  #     - "1ES.Pool=Onnxruntime-github-Linux-GPU-A100-WUS3"
+  #   permissions:
+  #     contents: read
+  #     packages: read
+  #   steps:
+  #     - name: Checkout code
+  #       uses: actions/checkout@v4
+
+  #     - uses: microsoft/onnxruntime-github-actions/[email protected]
+  #       id: build_docker_image_step
+  #       with:
+  #         dockerfile: ${{ github.workspace }}/tools/ci_build/github/linux/docker/Dockerfile.manylinux2_28_webgpu
+  #         image-name: ghcr.io/microsoft/onnxruntime/onnxruntimecpubuildcix64
+  #         push: true
+  #         azure-container-registry-name: onnxruntimebuildcache
+  #       env:
+  #         GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} # Pass token to action
+
+  #     # --- Download Build Artifact to Runner Temp Directory ---
+  #     - name: Download Build Artifact
+  #       uses: actions/download-artifact@v4
+  #       with:
+  #         name: build-output-x64-Release # Must match the upload name
+  #         path: ${{ runner.temp }}/Release # Download contents into temp dir structure
+
+  #     # --- Restore Permissions in the Temp Directory ---
+  #     - name: Restore Executable Permissions
+  #       if: success() # Only run if download succeeded
+  #       working-directory: ${{ runner.temp }}/Release
+  #       shell: bash
+  #       run: |
+  #         if [ -f perms.txt ]; then
+  #           echo "Restoring executable permissions in ${{ runner.temp }}/Release ..."
+  #           while IFS= read -r file; do
+  #             # Check relative path existence within the current directory
+  #             if [ -f "$file" ]; then
+  #               chmod +x "$file"
+  #             else
+  #               echo "Warning: File '$file' listed in perms.txt not found."
+  #             fi
+  #           done < perms.txt
+  #           echo "Permissions restored."
+  #         else
+  #           echo "Warning: perms.txt not found in artifact."
+  #         fi
+
+  #     - name: Test ONNX Runtime
+  #       id: test_step
+  #       uses: microsoft/onnxruntime-github-actions/[email protected]
+  #       with:
+  #         docker_image: ${{ steps.build_docker_image_step.outputs.full-image-name }}
+  #         build_config: Release
+  #         mode: 'test' # Set mode to test
+  #         execution_providers: 'webgpu'
+  #         extra_build_flags: '--use_binskim_compliant_compile_flags --cmake_extra_defines onnxruntime_BUILD_UNIT_TESTS=ON'
+  #         python_path_prefix: 'PATH=/opt/python/cp310-cp310/bin:$PATH'

tools/ci_build/github/linux/docker/Dockerfile.manylinux2_28_webgpu

@@ -0,0 +1,21 @@
+FROM onnxruntimebuildcache.azurecr.io/internal/azureml/onnxruntime/build/cpu_x64_ubi8_gcc14:20250124.1
+
+ENV JAVA_HOME=/usr/lib/jvm/msopenjdk-17
+
+#Install Vulkan and RPM Fusion for NVIDIA drivers (UBI8/RHEL8)
+RUN dnf install -y \
+    https://download1.rpmfusion.org/free/el/rpmfusion-free-release-8.noarch.rpm \
+    https://download1.rpmfusion.org/nonfree/el/rpmfusion-nonfree-release-8.noarch.rpm && \
+    dnf install -y xorg-x11-drv-nvidia akmod-nvidia vulkan vulkan-tools mesa-vulkan-drivers
+
+# TODO: Currently this Dockerfile works only for building WebGPU. Need to make it also support running WebGPU tests.
+
+ADD scripts /tmp/scripts
+RUN cd /tmp/scripts && /tmp/scripts/manylinux/install_centos.sh
+RUN cd /tmp/scripts && /tmp/scripts/manylinux/install_deps.sh && rm -rf /tmp/scripts
+
+ARG BUILD_UID=1001
+ARG BUILD_USER=onnxruntimedev
+RUN adduser --uid $BUILD_UID $BUILD_USER
+WORKDIR /home/$BUILD_USER
+USER $BUILD_USER