fix(ui-tests): install a real localizer in UsagePillViewModelTests

The pill tests asserted on real localized strings but never set Loc.Current,
which defaults to a key-echo localizer. They only passed because an unrelated
test class happened to install a real Localizer first; adding the usage-monitor
modal tests changed the ordering and the assertions started seeing raw keys.

Initialize Loc.Current in the constructor, matching every other UI test class.

tests/ClaudeDo.Ui.Tests/ViewModels/UsagePillViewModelTests.cs

@@ -1,4 +1,7 @@
 using System;
+using System.IO;
+using ClaudeDo.Localization;
+using ClaudeDo.Ui.Localization;
 using ClaudeDo.Ui.Services;
 using ClaudeDo.Ui.ViewModels;
 using Xunit;
@@ -7,6 +10,18 @@ namespace ClaudeDo.Ui.Tests.ViewModels;
 
 public class UsagePillViewModelTests
 {
+    // Loc.Current is ambient static state defaulting to a key-echo localizer, so these
+    // assertions on real strings must install a real one instead of relying on whichever
+    // other test class happened to run first.
+    public UsagePillViewModelTests()
+    {
+        var dir = AppContext.BaseDirectory;
+        while (dir is not null && !Directory.Exists(Path.Combine(dir, "src", "ClaudeDo.Localization", "locales")))
+            dir = Path.GetDirectoryName(dir);
+        Loc.Current = new Localizer(
+            LocaleStore.Load(Path.Combine(dir!, "src", "ClaudeDo.Localization", "locales")), "en");
+    }
+
     private sealed class FakeWorker : StubWorkerClient
     {
         public UsageSnapshotDto? InitialSnapshot;