fix(merge): conventional merge-commit default and live verify progress

The merge commit message was hand-rolled per caller ("Merge task: <title>",
"Merge <branch>", "Merge subtask") and ignored the task's commit type. Every
caller now passes a blank message and TaskMergeService fills in
CommitMessageBuilder.BuildMerge -> {commitType}(list-slug): merge <title> plus the
ClaudeDo-Task trailer; the merge modal prefills it from GetMergeTargets.

A merge whose list has a verify command holds the MergeTask call for minutes (5m46s
on this repo), during which the modal only disabled its button - no spinner, no
message, so a landed merge looked like a dead app. TaskMergeService now broadcasts
MergeProgress(taskId, phase, elapsedSeconds) for the merging and verifying phases
(re-reported every 30s) plus a WorkerLog line when verify starts; the modal shows a
spinner and the localized phase.

tests/ClaudeDo.Worker.Tests/Runner/CommitMessageBuilderTests.cs

@@ -65,6 +65,39 @@ public class CommitMessageBuilderTests
         Assert.Equal("ClaudeDo-Task: id-456", lines[4]);
     }
 
+    [Fact]
+    public void BuildMerge_ConventionalHeaderWithMergeVerbAndTrailer()
+    {
+        var msg = CommitMessageBuilder.BuildMerge("fix", "Lager App", "stop the crash", "id-789");
+        var lines = msg.Split('\n');
+
+        Assert.Equal("fix(lager-app): merge stop the crash", lines[0]);
+        Assert.Equal("", lines[1]);
+        Assert.Equal("ClaudeDo-Task: id-789", lines[2]);
+    }
+
+    [Fact]
+    public void BuildMerge_BlankCommitType_FallsBackToDefault()
+    {
+        var msg = CommitMessageBuilder.BuildMerge("  ", "My List", "do it", "id");
+        Assert.StartsWith("chore(my-list): merge do it", msg);
+    }
+
+    [Fact]
+    public void BuildMerge_ListNameWithoutSluggableChars_DropsScope()
+    {
+        var msg = CommitMessageBuilder.BuildMerge("feat", "!!!", "do it", "id");
+        Assert.StartsWith("feat: merge do it", msg);
+    }
+
+    [Fact]
+    public void BuildMerge_TitleTruncatedTo60()
+    {
+        var msg = CommitMessageBuilder.BuildMerge("feat", "My List", new string('x', 80), "id");
+        var titlePart = msg.Split('\n')[0].Split(": merge ", 2)[1];
+        Assert.Equal(60, titlePart.Length);
+    }
+
     [Fact]
     public void Description_TruncatedTo400()
     {

tests/ClaudeDo.Worker.Tests/Services/TaskMergeServiceTests.cs

@@ -283,6 +283,80 @@ public class TaskMergeServiceTests : IDisposable
         Assert.DoesNotContain(proxy.Calls, c => c.Method == "WorktreeUpdated");
     }
 
+    [Fact]
+    public async Task MergeAsync_BlankCommitMessage_UsesConventionalDefault()
+    {
+        if (!GitRepoFixture.IsGitAvailable()) return;
+
+        var repo = NewRepo();
+        var db = NewDb();
+        var (list, task) = await SeedListAndTask(db, workingDir: repo.RepoDir, status: TaskStatus.Done);
+
+        var wtMgr = BuildWorktreeManager(db);
+        var wtCtx = await wtMgr.CreateAsync(task, list, CancellationToken.None);
+        _wtCleanups.Add((repo.RepoDir, wtCtx.WorktreePath));
+        File.WriteAllText(Path.Combine(wtCtx.WorktreePath, "feature.txt"), "feat\n");
+        await wtMgr.CommitIfChangedAsync(wtCtx, task, list, CancellationToken.None);
+
+        var (svc, _) = BuildService(db);
+        var currentBranch = await new GitService().GetCurrentBranchAsync(repo.RepoDir);
+
+        var result = await svc.MergeAsync(task.Id, currentBranch, removeWorktree: false,
+            commitMessage: "", ct: CancellationToken.None);
+
+        Assert.Equal("merged", result.Status);
+        var subject = GitRepoFixture.RunGit(repo.RepoDir, "log", "-1", "--format=%s").Trim();
+        // task.CommitType (not the list default) — same type the task's own commits used.
+        Assert.Equal($"{task.CommitType}(merge-test): merge merge-task", subject);
+        var body = GitRepoFixture.RunGit(repo.RepoDir, "log", "-1", "--format=%b");
+        Assert.Contains($"ClaudeDo-Task: {task.Id}", body);
+    }
+
+    [Fact]
+    public async Task MergeAsync_VerifyGate_BroadcastsMergingAndVerifyingPhases()
+    {
+        if (!GitRepoFixture.IsGitAvailable()) return;
+
+        var repo = NewRepo();
+        var db = NewDb();
+        var (list, task) = await SeedListAndTask(db, workingDir: repo.RepoDir, status: TaskStatus.Done);
+        await SeedVerifyCommand(db, list.Id, "echo ok");
+
+        var wtMgr = BuildWorktreeManager(db);
+        var wtCtx = await wtMgr.CreateAsync(task, list, CancellationToken.None);
+        _wtCleanups.Add((repo.RepoDir, wtCtx.WorktreePath));
+        File.WriteAllText(Path.Combine(wtCtx.WorktreePath, "feature.txt"), "feat\n");
+        await wtMgr.CommitIfChangedAsync(wtCtx, task, list, CancellationToken.None);
+
+        var (svc, proxy) = BuildService(db, new FakeVerifyCommandRunner());
+        var currentBranch = await new GitService().GetCurrentBranchAsync(repo.RepoDir);
+
+        var result = await svc.MergeAsync(task.Id, currentBranch, removeWorktree: false,
+            commitMessage: "", ct: CancellationToken.None);
+
+        Assert.Equal("merged", result.Status);
+        Assert.Contains(proxy.Calls, c => c.Method == "MergeProgress"
+            && (string?)c.Args[0] == task.Id && (string?)c.Args[1] == TaskMergeService.PhaseMerging);
+        Assert.Contains(proxy.Calls, c => c.Method == "MergeProgress"
+            && (string?)c.Args[0] == task.Id && (string?)c.Args[1] == TaskMergeService.PhaseVerifying);
+        Assert.Contains(proxy.Calls, c => c.Method == "WorkerLog"
+            && c.Args[0] is string s && s.Contains("Verify command running"));
+    }
+
+    [Fact]
+    public async Task GetTargetsAsync_ReturnsDefaultCommitMessage()
+    {
+        if (!GitRepoFixture.IsGitAvailable()) return;
+        var repo = NewRepo();
+        var db = NewDb();
+        var (_, task) = await SeedListAndTask(db, workingDir: repo.RepoDir, status: TaskStatus.Done);
+
+        var (svc, _) = BuildService(db);
+        var targets = await svc.GetTargetsAsync(task.Id, CancellationToken.None);
+
+        Assert.Equal($"{task.CommitType}(merge-test): merge merge-task", targets.DefaultCommitMessage.Split('\n')[0]);
+    }
+
     [Fact]
     public async Task GetTargetsAsync_ReturnsCurrentAndLocalBranches()
     {

tests/ClaudeDo.Worker.Tests/UiVm/TasksIslandViewModelPlanningTests.cs

@@ -113,6 +113,7 @@ sealed class FakeWorkerClient : IWorkerClient
     public event Action<bool>? PrepFinishedEvent;
     public event Action<string>? RefineStartedEvent;
     public event Action<string, bool, string?>? RefineFinishedEvent;
+    public event Action<string, string, int>? MergeProgressEvent;
     public event Action<string, string>? PlanningMergeStartedEvent;
     public event Action<string, string>? PlanningSubtaskMergedEvent;
     public event Action<string, string, IReadOnlyList<string>, bool>? PlanningMergeConflictEvent;