Apply code style formatting and restore partial modifiers on Avalonia views

Linter/formatter pass across the full codebase. Restores required partial
keyword on AXAML code-behind classes that the formatter incorrectly removed.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/ZB.MOM.WW.LmxOpcUa.Client.UI.Tests/SubscriptionsViewModelTests.cs

@@ -168,4 +168,4 @@ public class SubscriptionsViewModelTests
         _vm.ActiveSubscriptions.ShouldBeEmpty();
         _service.SubscribeCallCount.ShouldBe(0);
     }
-}
+}