feat(installer): default to a per-user ArtCraft folder

.github/workflows/packaging-lint.yml

@@ -23,3 +23,22 @@ jobs:
     uses: storytold/craft-common-actions/.github/workflows/packaging-lint.yml@main
     with:
       extra-checks-script: packaging/check-app-specific.sh
+
+  windows-install-policy:
+    timeout-minutes: 10
+    name: Windows installation policy (no app build)
+    runs-on: windows-latest
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+      - name: Install the pinned packaging toolchain
+        shell: pwsh
+        run: |
+          $tools = Join-Path $env:RUNNER_TEMP 'craft-install-policy-wix'
+          dotnet tool install --tool-path $tools wix --version 5.0.2
+          if ($LASTEXITCODE -ne 0) { throw 'WiX installation failed.' }
+          $tools >> $env:GITHUB_PATH
+          & (Join-Path $tools 'wix.exe') extension add -g WixToolset.UI.wixext/5.0.2 WixToolset.Util.wixext/5.0.2
+          if ($LASTEXITCODE -ne 0) { throw 'WiX extension installation failed.' }
+      - name: Build and check non-executable installer fixtures
+        shell: pwsh
+        run: ./packaging/windows/test-install-policy.ps1 -OutputDirectory (Join-Path $env:RUNNER_TEMP 'craft-install-policy-tests')