fix(ui): silent no-ops raise ErrorReported instead of swallowing failures (UX-Audit #1)

Stop/Enqueue/Dequeue/Reset&Retry (DetailsIslandViewModel), status/cancel/reject
commands (TasksIslandViewModel), Mission Control's drag-enqueue and queue
refresh, and "Open findings folder" (ListsIslandViewModel) used to catch {}
or silently return on a blocked precondition. They now report through the
existing ErrorReported -> FlashFooterError path, with new en/de locale keys
and Ui.Tests covering each converted command.

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

@@ -0,0 +1,73 @@
+using ClaudeDo.Data;
+using ClaudeDo.Localization;
+using ClaudeDo.Ui.Localization;
+using ClaudeDo.Ui.ViewModels.Islands;
+using Microsoft.EntityFrameworkCore;
+
+namespace ClaudeDo.Ui.Tests.ViewModels;
+
+// UX-Audit #1: "Open findings folder" used to do nothing when the list's repo has no
+// .claudedo/ folder yet — now it raises ErrorReported instead of a silent no-op.
+public class ListsIslandErrorFeedbackTests : IDisposable
+{
+    private readonly string _dbPath;
+
+    public ListsIslandErrorFeedbackTests()
+    {
+        _dbPath = Path.Combine(Path.GetTempPath(), $"claudedo_lists_error_feedback_test_{Guid.NewGuid():N}.db");
+        using var ctx = NewContext();
+        ctx.Database.EnsureCreated();
+
+        var dir = AppContext.BaseDirectory;
+        while (dir is not null && !Directory.Exists(Path.Combine(dir, "src", "ClaudeDo.Localization", "locales")))
+            dir = Path.GetDirectoryName(dir);
+        Loc.Current = new Localizer(
+            LocaleStore.Load(Path.Combine(dir!, "src", "ClaudeDo.Localization", "locales")), "en");
+    }
+
+    public void Dispose()
+    {
+        try { File.Delete(_dbPath); } catch { }
+        try { File.Delete(_dbPath + "-wal"); } catch { }
+        try { File.Delete(_dbPath + "-shm"); } catch { }
+    }
+
+    private ClaudeDoDbContext NewContext()
+    {
+        var opts = new DbContextOptionsBuilder<ClaudeDoDbContext>()
+            .UseSqlite($"Data Source={_dbPath}")
+            .Options;
+        return new ClaudeDoDbContext(opts);
+    }
+
+    private sealed class TestDbFactory : IDbContextFactory<ClaudeDoDbContext>
+    {
+        private readonly Func<ClaudeDoDbContext> _create;
+        public TestDbFactory(Func<ClaudeDoDbContext> create) => _create = create;
+        public ClaudeDoDbContext CreateDbContext() => _create();
+    }
+
+    [Fact]
+    public void OpenFindings_WhenClaudedoFolderMissing_RaisesErrorReported()
+    {
+        var vm = new ListsIslandViewModel(new TestDbFactory(NewContext));
+        var workingDir = Path.Combine(Path.GetTempPath(), $"claudedo_findings_missing_{Guid.NewGuid():N}");
+        Directory.CreateDirectory(workingDir);
+        try
+        {
+            var row = new ListNavItemViewModel { Id = "L1", Kind = ListKind.User, WorkingDir = workingDir };
+
+            string? reportedError = null;
+            vm.ErrorReported += msg => reportedError = msg;
+
+            vm.OpenFindingsCommand.Execute(row);
+
+            Assert.NotNull(reportedError);
+            Assert.NotEqual(string.Empty, reportedError);
+        }
+        finally
+        {
+            try { Directory.Delete(workingDir, recursive: true); } catch { }
+        }
+    }
+}