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/TasksIslandErrorFeedbackTests.cs

@@ -0,0 +1,149 @@
+using ClaudeDo.Data;
+using ClaudeDo.Data.Models;
+using ClaudeDo.Localization;
+using ClaudeDo.Ui.Localization;
+using ClaudeDo.Ui.Services;
+using ClaudeDo.Ui.ViewModels.Islands;
+using Microsoft.EntityFrameworkCore;
+using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
+
+namespace ClaudeDo.Ui.Tests.ViewModels;
+
+// UX-Audit #1: SetStatusOnRow/CancelRunningTask/RejectReviewToQueue/RejectReviewToIdle used
+// to swallow worker failures with a bare `catch { }` — nothing surfaced in the footer strip.
+// These now raise ErrorReported.
+public class TasksIslandErrorFeedbackTests : IDisposable
+{
+    private readonly string _dbPath;
+
+    public TasksIslandErrorFeedbackTests()
+    {
+        _dbPath = Path.Combine(Path.GetTempPath(), $"claudedo_tasksisland_error_feedback_test_{Guid.NewGuid():N}.db");
+        using var ctx = NewContext();
+        ctx.Database.EnsureCreated();
+
+        var dir = AppContext.BaseDirectory;
+        while (dir is not null && !Directory.Exists(Path.Combine(dir, "src", "ClaudeDo.Localization", "locales")))
+            dir = Path.GetDirectoryName(dir);
+        Loc.Current = new Localizer(
+            LocaleStore.Load(Path.Combine(dir!, "src", "ClaudeDo.Localization", "locales")), "en");
+    }
+
+    public void Dispose()
+    {
+        try { File.Delete(_dbPath); } catch { }
+        try { File.Delete(_dbPath + "-wal"); } catch { }
+        try { File.Delete(_dbPath + "-shm"); } catch { }
+    }
+
+    private ClaudeDoDbContext NewContext()
+    {
+        var opts = new DbContextOptionsBuilder<ClaudeDoDbContext>()
+            .UseSqlite($"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();
+    }
+
+    private sealed class ThrowingWorkerClient : StubWorkerClient
+    {
+        public Exception? ThrowOnSetTaskStatus;
+        public Exception? ThrowOnCancelTask;
+        public Exception? ThrowOnRejectToQueue;
+        public Exception? ThrowOnRejectToIdle;
+
+        public override Task<BaseDirtyWarningDto?> SetTaskStatusAsync(string taskId, TaskStatus status)
+        {
+            if (ThrowOnSetTaskStatus is not null) throw ThrowOnSetTaskStatus;
+            return Task.FromResult<BaseDirtyWarningDto?>(null);
+        }
+
+        public override Task CancelTaskAsync(string taskId)
+        {
+            if (ThrowOnCancelTask is not null) throw ThrowOnCancelTask;
+            return Task.CompletedTask;
+        }
+
+        public override Task RejectReviewToQueueAsync(string taskId, string feedback)
+        {
+            if (ThrowOnRejectToQueue is not null) throw ThrowOnRejectToQueue;
+            return Task.CompletedTask;
+        }
+
+        public override Task RejectReviewToIdleAsync(string taskId)
+        {
+            if (ThrowOnRejectToIdle is not null) throw ThrowOnRejectToIdle;
+            return Task.CompletedTask;
+        }
+    }
+
+    [Fact]
+    public async Task SetStatusOnRow_WhenWorkerThrows_RaisesErrorReported()
+    {
+        var worker = new ThrowingWorkerClient { ThrowOnSetTaskStatus = new Exception("status update offline") };
+        var vm = new TasksIslandViewModel(new TestDbFactory(NewContext), worker);
+
+        string? reportedError = null;
+        vm.ErrorReported += msg => reportedError = msg;
+
+        var row = new TaskRowViewModel { Id = "task-status-1", Status = TaskStatus.Idle };
+        await vm.SetStatusOnRowAsync(row, TaskStatus.Queued);
+
+        Assert.NotNull(reportedError);
+        Assert.Contains("status update offline", reportedError);
+    }
+
+    [Fact]
+    public async Task CancelRunningTask_WhenWorkerThrows_RaisesErrorReported()
+    {
+        var worker = new ThrowingWorkerClient { ThrowOnCancelTask = new Exception("cancel offline") };
+        var vm = new TasksIslandViewModel(new TestDbFactory(NewContext), worker);
+
+        string? reportedError = null;
+        vm.ErrorReported += msg => reportedError = msg;
+
+        var row = new TaskRowViewModel { Id = "task-cancel-1", Status = TaskStatus.Running };
+        await vm.CancelRunningTaskCommand.ExecuteAsync(row);
+
+        Assert.NotNull(reportedError);
+        Assert.Contains("cancel offline", reportedError);
+    }
+
+    [Fact]
+    public async Task RejectReviewToQueue_WhenWorkerThrows_RaisesErrorReported()
+    {
+        var worker = new ThrowingWorkerClient { ThrowOnRejectToQueue = new Exception("reject-to-queue offline") };
+        var vm = new TasksIslandViewModel(new TestDbFactory(NewContext), worker);
+
+        string? reportedError = null;
+        vm.ErrorReported += msg => reportedError = msg;
+
+        var row = new TaskRowViewModel { Id = "task-reject-queue-1", Status = TaskStatus.WaitingForReview };
+        await vm.RejectReviewToQueueAsync(row, "needs another pass");
+
+        Assert.NotNull(reportedError);
+        Assert.Contains("reject-to-queue offline", reportedError);
+    }
+
+    [Fact]
+    public async Task RejectReviewToIdle_WhenWorkerThrows_RaisesErrorReported()
+    {
+        var worker = new ThrowingWorkerClient { ThrowOnRejectToIdle = new Exception("reject-to-idle offline") };
+        var vm = new TasksIslandViewModel(new TestDbFactory(NewContext), worker);
+
+        string? reportedError = null;
+        vm.ErrorReported += msg => reportedError = msg;
+
+        var row = new TaskRowViewModel { Id = "task-reject-idle-1", Status = TaskStatus.WaitingForReview };
+        await vm.RejectReviewToIdleCommand.ExecuteAsync(row);
+
+        Assert.NotNull(reportedError);
+        Assert.Contains("reject-to-idle offline", reportedError);
+    }
+}