Start Docker early and retry or fail-fast instead of after building wheels

.github/workflows/wheels.yml

@@ -217,6 +217,25 @@ jobs:
           & python.exe winbuild\build_prepare.py -v --no-imagequant --architecture=${{ matrix.cibw_arch }}
         shell: pwsh
 
+      # The wheel test runs in a Windows container, but the Docker daemon is
+      # not reliably running when cibuildwheel reaches the test step, which
+      # fails the job after the wheels have already been built. Start it and
+      # wait for it here instead, so a daemon problem is caught in seconds.
+      - name: Start Docker
+        if: matrix.cibw_arch != 'ARM64'
+        run: |
+          Start-Service docker
+          foreach ($i in 1..30) {
+            docker info *> $null
+            if ($LASTEXITCODE -eq 0) {
+              Write-Host "Docker daemon ready after $i attempt(s)"
+              exit 0
+            }
+            Start-Sleep -Seconds 2
+          }
+          Write-Error "Docker daemon did not become ready"
+        shell: pwsh
+
       - name: Build wheels
         run: |
           for f in winbuild/build/license/*; do