feat(daily-prep): add Prep-log and Clear-day buttons to MyDay header

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

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

@@ -0,0 +1,67 @@
+using ClaudeDo.Data;
+using ClaudeDo.Ui.ViewModels.Islands;
+using Microsoft.EntityFrameworkCore;
+
+namespace ClaudeDo.Ui.Tests.ViewModels;
+
+public class TasksIslandDailyPrepTests : IDisposable
+{
+    private readonly string _dbPath;
+
+    public TasksIslandDailyPrepTests()
+    {
+        _dbPath = Path.Combine(Path.GetTempPath(), $"claudedo_tasks_prep_{Guid.NewGuid():N}.db");
+        using var ctx = NewContext();
+        ctx.Database.EnsureCreated();
+    }
+
+    public void Dispose()
+    {
+        try { File.Delete(_dbPath); } catch { }
+        try { File.Delete(_dbPath + "-wal"); } catch { }
+        try { File.Delete(_dbPath + "-shm"); } catch { }
+    }
+
+    private ClaudeDoDbContext NewContext()
+    {
+        var opts = new DbContextOptionsBuilder<ClaudeDoDbContext>()
+            .UseSqlite($"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 DefaultStub : StubWorkerClient { }
+
+    private TasksIslandViewModel NewTasksVm(StubWorkerClient stub) =>
+        new(new TestDbFactory(NewContext), worker: stub);
+
+    [Fact]
+    public async Task ClearDayCommand_calls_worker()
+    {
+        var stub = new DefaultStub();
+        var vm = NewTasksVm(stub);
+
+        await vm.ClearDayCommand.ExecuteAsync(null);
+
+        Assert.Equal(1, stub.ClearMyDayCalls);
+    }
+
+    [Fact]
+    public async Task PrepareDayCommand_raises_PrepRequested()
+    {
+        var vm = NewTasksVm(new DefaultStub());
+        var raised = false;
+        vm.PrepRequested += () => raised = true;
+
+        await vm.PrepareDayCommand.ExecuteAsync(null);
+
+        Assert.True(raised);
+    }
+}