Fix missing WinGet updates (issue 4545)

[Gabriel Dufresne (GabrielDuf)]

Problem

Users reported that some packages shown as upgradable by winget upgrade were not appearing in the UniGetUI updates list. This regression was introduced in d324a0f, which changed WinGet COM activation to prefer the bundled in-proc DLL over the system COM registration.
The bundled WindowsPackageManager.dll does not reliably populate IsUpdateAvailable when the composite catalog uses CompositeSearchBehavior.LocalCatalogs, causing most updates to be silently skipped.

Fix

Introduced GetWinGetPackagesForUpdates(), a dedicated catalog query method for update detection that uses CompositeSearchBehavior.RemotePackagesFromAllCatalogs. This mirrors the behavior of winget upgrade internally and correctly resolves update availability against remote catalog data regardless of which COM activation mode is in use.

The existing GetLocalWinGetPackages() with LocalCatalogs is preserved for installed packages listing, where it
remains correct and efficient.

Also added an explicit null guard on DefaultInstallVersion in GetAvailableUpdates_UnSafe() to surface skipped
packages as warnings rather than silent exceptions.

[Copilot]

Pull request overview

Fixes a regression in WinGet update detection where packages reported by winget upgrade were not being surfaced in UniGetUI’s updates list when using bundled in-proc COM activation.

Changes:

• Switched WinGet update enumeration to use a dedicated composite catalog query (RemotePackagesFromAllCatalogs) intended to match winget upgrade’s behavior.
• Added a null-guard for DefaultInstallVersion to avoid exceptions and log skipped packages.

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[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 3 comments.

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