Avalonia: Feature parity with WinUI

[Gabriel Dufresne (GabrielDuf)]

This PR brings the Avalonia (cross-platform) port to full feature parity with the WinUI 3 application. The work covers every major surface area that was previously missing or incomplete.

Package lists & filter pane

• Resizable filter pane with GridSplitter (replaces fixed SplitView); auto-closes when dragged below 100 px; switches to overlay mode on narrow windows
• Per-page filter-pane width and overlay-state persistence across navigation
• Hierarchical sources tree in the filter pane
• Package tag state badges (installed, upgradable, pinned, on-queue, processing, failed)
• Custom package icons loaded and displayed in list, grid, and icon views
• Type-to-search with a global search-box focus API

Operations panel

• Bulk operations (queue all, cancel all, retry all)
• Expand/collapse all output cards
• Per-card expand button in grid and icon views
• Per-line color coding in the operation output window

Package details & install options

• Installation options accessible from the package details window
• InstallOptionsControl extracted as a reusable component; InstallOptionsWindow reuses it

Operations & dialogs

• AvaloniaPackageOperationHelper — full operation lifecycle (install, update, uninstall, custom)
• OperationFailedDialog, MissingDependencyDialog, IntegrityViolationDialog, SimpleErrorDialog, BundleSecurityReportDialog, DiscardBundleChangesDialog - Windows tray icon service
• CLI argument handler (AvaloniaCliHandler)
• Crash handler

Settings & backup

• Clear-successful-operations setting
• Cloud backup triggered on app load
• Metered-connection auto-update gate

Platform & infrastructure

• WebView with Windows implementation and Linux fallback
• AvaloniaOperationRegistry and AvaloniaBootstrapper for operation wiring
• App manifest updated for Windows UAC / DPI awareness
• Chocolatey package build script added

[Aryan Choudhary (aryanchoudharypro)]

Hello, just wanted to clarify if you plann to discontinue the win ui 3 version. If yes, i'd Appreciate if you could keep screen reader accessibility in mind when developing this new version. Thanks.

[Gabriel Dufresne (GabrielDuf)]

Aryan Choudhary (@aryanchoudharypro),
Hello! Yes, the plan is to eventually move fully to Avalonia since it allows us to support multiple platforms more effectively. Accessibility is definitely something we’re keeping in mind during this transition.

I’ve already started working on some accessibility layers, and if you’re interested, you can take a look at this PR: #4582

[Aryan Choudhary (aryanchoudharypro)]

Aryan Choudhary (Aryan Choudhary (@aryanchoudharypro)), Hello! Yes, the plan is to eventually move fully to Avalonia since it allows us to support multiple platforms more effectively. Accessibility is definitely something we’re keeping in mind during this transition.

I’ve already started working on some accessibility layers, and if you’re interested, you can take a look at this PR: #4582

seems very comprehensive, i myself will also try to support that accessibility support as much as i can manage!