Fix -PreferedInstaller being ignored for zip packages with NestedInstallerType

[Copilot]

For packages like dotPDN.PaintDotNet that use InstallerType: zip with a NestedInstallerType: wix, specifying -PreferedInstaller Wix had no effect — the matcher only checked the outer InstallerType field ("zip"), never matching "wix".

Changes

• WingetInstallerExtensions: Extended singleOrDefault to also match a zip installer when its NestedInstallerType equals the requested type. Logic extracted into a new InstallerTypeMatches helper:

private static bool InstallerTypeMatches(WingetInstaller installer, InstallerType requestedType)
{
    if (requestedType == InstallerType.Unknown) return true;
    if (installer.ParseInstallerType() == requestedType) return true;
    // For zip installers, also match by NestedInstallerType
    return installer.ParseInstallerType() == InstallerType.Zip
        && !string.IsNullOrEmpty(installer.NestedInstallerType)
        && EnumParsers.ParseInstallerType(installer.NestedInstallerType) == requestedType;
}

• Tests: Added PackageInfo unit tests verifying that InstallerType.Wix preference selects a zip+wix installer, plus a WingetManager integration test for the PaintDotNet manifest (zip outer / wix nested).

[github-actions]

Test Results

14 tests  ±0   13 ✅ ±0   2s ⏱️ ±0s
10 suites ±0    1 💤 ±0 
 1 files   ±0    0 ❌ ±0 

Results for commit 0b902bf. ± Comparison against base commit 84b622b.