feat(mission-control): give the list handler its own review task

"Let Claude handle it" now creates one ClaudeDo task per run to host the
ConPTY session (Idle/IsManual, never queued) instead of an untracked
ad-hoc tile, so the run has a real title, diff, and review outcome.
Since the handler merges its own changes straight into the list's
working dir, the task never gets a WorktreeEntity; its review range
lives as new HandlerBaseCommit/HandlerHeadCommit columns on TaskEntity
instead, reusing the existing commit-range diff machinery and keeping
it out of the worktrees overview entirely.

src/ClaudeDo.Ui/Services/Interfaces/IWorkerClient.cs

@@ -88,6 +88,10 @@ public interface IWorkerClient : INotifyPropertyChanged
     /// <summary>Launch spec for an embedded ConPTY "merge helper" session that drives the given
     /// tasks to a merged/Done state. listId scopes the session (and cwd) to that list.</summary>
     Task<LaunchSpec> GetMergeHelperLaunchSpecAsync(IReadOnlyList<string> taskIds, string listId, CancellationToken ct = default);
+    /// <summary>Creates the ClaudeDo task that owns a list-handler run (one per run, Idle/IsManual,
+    /// never queued) so the ConPTY tile can be task-based instead of ad-hoc. Returns the new task id.</summary>
+    Task<string> CreateMergeHelperTaskAsync(
+        IReadOnlyList<string> taskIds, string listId, string title, string descriptionHeader, CancellationToken ct = default);
     /// <summary>Starts a planning session and returns the launch spec for an embedded ConPTY
     /// planning terminal (replaces StartPlanningSessionAsync's external wt window).</summary>
     Task<LaunchSpec> GetPlanningStartLaunchSpecAsync(string taskId, CancellationToken ct = default);