Experimental Changes to Avalonia

[taooceros]

Summary

• honor Settings.LastQueryMode in Avalonia MainViewModel.Show() / Hide() instead of always clearing QueryText
• keep query text mutations hidden from the user: hide before Empty/action-keyword reset/rewrite, and stage show while the window is transparent
• fix the remaining visible selection motion by making QueryTextFocusRequest own the first visible show: Show() / ShowWithInjectedQuery(...) now raise the focus request before MainWindowVisibility = true, so the IsVisible binding cannot reveal the window before staging
• for hidden-window shows, force the TextBox.Text target to the ViewModel query text, wait until DispatcherPriority.ContextIdle before applying focus/selection, then reveal at render priority
• for LastQueryMode.Selected, apply the pre-hide select-all request while MainWindowVisibility is still true, then hide; next show uses focus-only mode when selection is already prepared
• keep selection/caret updates in the existing QueryTextFocusRequest path; no DWM cloak is used
• add focused Avalonia ViewModel tests for LastQueryMode behavior plus show/hide visibility ordering

Verification

• dotnet test Flow.Launcher.Test/Flow.Launcher.Test.csproj --no-restore --filter FullyQualifiedName~Flow.Launcher.Test.Avalonia.MainViewModelLastQueryModeTest
  • Passed: 10, Failed: 0, Skipped: 0
• dotnet build Flow.Launcher.Avalonia/Flow.Launcher.Avalonia.csproj -c Debug --no-restore
  • Build succeeded: 12 warnings, 0 errors