feat(worker): expose ResetTask hub method

Wire TaskResetService into DI and add WorkerHub.ResetTask with the
same InvalidOperationException/KeyNotFoundException error-translation
pattern as ContinueTask.

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

src/ClaudeDo.Worker/Hub/WorkerHub.cs

@@ -33,19 +33,22 @@ public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
     private readonly HubBroadcaster _broadcaster;
     private readonly IDbContextFactory<ClaudeDoDbContext> _dbFactory;
     private readonly WorktreeMaintenanceService _wtMaintenance;
+    private readonly TaskResetService _resetService;
 
     public WorkerHub(
         QueueService queue,
         AgentFileService agentService,
         HubBroadcaster broadcaster,
         IDbContextFactory<ClaudeDoDbContext> dbFactory,
-        WorktreeMaintenanceService wtMaintenance)
+        WorktreeMaintenanceService wtMaintenance,
+        TaskResetService resetService)
     {
         _queue = queue;
         _agentService = agentService;
         _broadcaster = broadcaster;
         _dbFactory = dbFactory;
         _wtMaintenance = wtMaintenance;
+        _resetService = resetService;
     }
 
     public string Ping() => $"pong v{Version}";
@@ -89,6 +92,22 @@ public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
         }
     }
 
+    public async Task ResetTask(string taskId)
+    {
+        try
+        {
+            await _resetService.ResetAsync(taskId, CancellationToken.None);
+        }
+        catch (InvalidOperationException ex)
+        {
+            throw new HubException(ex.Message);
+        }
+        catch (KeyNotFoundException)
+        {
+            throw new HubException("task not found");
+        }
+    }
+
     public bool CancelTask(string taskId) => _queue.CancelTask(taskId);
 
     public void WakeQueue() => _queue.WakeQueue();

src/ClaudeDo.Worker/Program.cs

@@ -30,6 +30,7 @@ builder.Services.AddSingleton<WorktreeManager>();
 builder.Services.AddSingleton<ClaudeArgsBuilder>();
 builder.Services.AddSingleton<TaskRunner>();
 builder.Services.AddSingleton<WorktreeMaintenanceService>();
+builder.Services.AddSingleton<TaskResetService>();
 
 // Agent file management.
 var agentsDir = Path.Combine(ClaudeDo.Data.Paths.AppDataRoot(), "agents");