feat(ui): add worker log state and 30s timer to shell VM

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/ClaudeDo.Ui.Tests/IslandsShellViewModelWorkerLogTests.cs

@@ -0,0 +1,58 @@
+using System;
+using ClaudeDo.Data.Models;
+using ClaudeDo.Ui.Services;
+using ClaudeDo.Ui.ViewModels;
+using Xunit;
+
+namespace ClaudeDo.Ui.Tests;
+
+public class IslandsShellViewModelWorkerLogTests
+{
+    [Fact]
+    public void Receiving_event_sets_text_level_and_visible()
+    {
+        var vm = new IslandsShellViewModel();
+        var at = new DateTime(2026, 4, 23, 14, 32, 0, DateTimeKind.Utc);
+
+        vm.OnWorkerLogReceived(new WorkerLogEntry("Created worktree for \"X\"", WorkerLogLevel.Info, at));
+
+        Assert.True(vm.IsWorkerLogVisible);
+        Assert.Equal(WorkerLogLevel.Info, vm.WorkerLogLevel);
+        Assert.Contains("Created worktree for \"X\"", vm.WorkerLogText);
+    }
+
+    [Fact]
+    public void Second_event_replaces_first()
+    {
+        var vm = new IslandsShellViewModel();
+        vm.OnWorkerLogReceived(new WorkerLogEntry("first", WorkerLogLevel.Info,    DateTime.UtcNow));
+        vm.OnWorkerLogReceived(new WorkerLogEntry("second", WorkerLogLevel.Success, DateTime.UtcNow));
+
+        Assert.Contains("second", vm.WorkerLogText);
+        Assert.Equal(WorkerLogLevel.Success, vm.WorkerLogLevel);
+    }
+
+    [Fact]
+    public void ClearWorkerLog_hides_line()
+    {
+        var vm = new IslandsShellViewModel();
+        vm.OnWorkerLogReceived(new WorkerLogEntry("msg", WorkerLogLevel.Info, DateTime.UtcNow));
+
+        vm.ClearWorkerLog();
+
+        Assert.False(vm.IsWorkerLogVisible);
+        Assert.Null(vm.WorkerLogText);
+    }
+
+    [Fact]
+    public void Text_is_formatted_as_HHmm_dot_message_local_time()
+    {
+        var vm = new IslandsShellViewModel();
+        var utc = new DateTime(2026, 4, 23, 12, 0, 0, DateTimeKind.Utc);
+        var expectedLocalHhmm = utc.ToLocalTime().ToString("HH:mm");
+
+        vm.OnWorkerLogReceived(new WorkerLogEntry("hello", WorkerLogLevel.Info, utc));
+
+        Assert.StartsWith(expectedLocalHhmm + " · ", vm.WorkerLogText);
+    }
+}