ci(workflows): 修复Windows构建中Git路径和PATH更新的问题

修复Git路径检查使用绝对路径以避免PATH传播时序问题，并确保PATH更新立即生效

.github/workflows/build-windows.yml

@@ -87,13 +87,22 @@ jobs:
         )
         foreach ($p in $paths) {
           if (Test-Path $p) {
+            # Make available to subsequent steps
             Add-Content -Path $env:GITHUB_PATH -Value $p
+            # Also update current step PATH so we can verify immediately
+            $env:PATH = "$p;$env:PATH"
             Write-Host "✅ Added to PATH: $p"
           } else {
             Write-Host "⚠️ Path not found: $p"
           }
         }
-        git --version
+        # Verify Git using absolute path to avoid PATH propagation timing issues
+        $gitCmd = 'C:\Program Files\Git\cmd\git.exe'
+        if (Test-Path $gitCmd) {
+          & $gitCmd --version
+        } else {
+          Write-Host "ℹ️ Git executable not found at $gitCmd; continuing."
+        }
 
     - name: 📥 Checkout 代码
       uses: actions/checkout@v4