CI: Move Windows build to ci.yml using new Blacksmith runners

.github/actions/setup/action.yml

@@ -54,6 +54,20 @@ runs:
         sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-14 100
         sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-14 100
 
+    - name: Ensure clang-cl is available
+      if: ${{ inputs.os == 'Windows' && inputs.toolchain == 'ClangCL' }}
+      shell: bash
+      run: |
+        if ! where clang-cl > /dev/null 2>&1 ; then
+          # Keep the LLVM version in sync with GitHub's Windows runner image:
+          # https://github.com/actions/runner-images/blob/main/images/windows/Windows2025-Readme.md
+          choco install -y llvm --no-progress --version=20.1.8
+
+          echo "C:/Program Files/LLVM/bin" >> "${GITHUB_PATH}"
+          export PATH="/c/Program Files/LLVM/bin:${PATH}"
+        fi
+        clang-cl --version
+
     - name: 'Select latest Xcode'
       if: ${{ inputs.os == 'macOS' || inputs.os == 'Android' }}
       uses: maxim-lobanov/setup-xcode@v1

.github/workflows/ci-windows.yml

@@ -1,33 +0,0 @@
-name: CI (Windows)
-
-on:
-  pull_request:
-    types:
-      - opened
-      - synchronize
-      - reopened
-      - labeled
-      - unlabeled
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.ref }}
-  # Do not cancel in-progress runs if a labeling action took place (other than 'windows'). Otherwise, adding irrelevant
-  # labels causes existing runs to be canceled and a new (identical) run to be started.
-  cancel-in-progress: ${{ (github.event.action != 'labeled' && github.event.action != 'unlabeled') || github.event.label.name == 'windows' }}
-
-jobs:
-  CI:
-    # Only run this job if the PR has the 'windows' label.
-    if: |
-      github.repository == 'LadybirdBrowser/ladybird'
-      && contains(github.event.pull_request.labels.*.name, 'windows')
-    name: 'Windows, x86_64, Windows_Sanitizer_CI, ClangCL'
-    secrets: inherit
-    uses: ./.github/workflows/lagom-template.yml
-    with:
-      toolchain: 'ClangCL'
-      os_name: 'Windows'
-      runner_labels: '["windows-2025"]'
-      arch: 'x86_64'
-      build_preset: 'Windows_Sanitizer_CI'
-      clang_plugins: false

.github/workflows/ci.yml

@@ -58,6 +58,13 @@ jobs:
             clang_plugins: false
             runner_labels: '["blacksmith-16vcpu-ubuntu-2404"]'
 
+          - os_name: 'Windows'
+            arch: 'x86_64'
+            build_preset: 'Windows_Sanitizer_CI'
+            toolchain: 'ClangCL'
+            clang_plugins: false
+            runner_labels: '["blacksmith-16vcpu-windows-2025"]'
+
     secrets: inherit
     uses: ./.github/workflows/lagom-template.yml
     with: