feat(worker): add ContinueTask routing to QueueService

src/ClaudeDo.Worker/Services/QueueService.cs

@@ -75,6 +75,31 @@ public sealed class QueueService : BackgroundService
         }
     }
 
+    public async Task<string> ContinueTask(string taskId, string followUpPrompt)
+    {
+        var task = await _taskRepo.GetByIdAsync(taskId)
+            ?? throw new KeyNotFoundException($"Task '{taskId}' not found.");
+
+        if (task.Status == Data.Models.TaskStatus.Running)
+            throw new InvalidOperationException("Task is currently running.");
+
+        lock (_lock)
+        {
+            if (_overrideSlot is not null)
+                throw new InvalidOperationException("override slot busy");
+
+            var cts = new CancellationTokenSource();
+            _overrideSlot = new QueueSlotState { TaskId = taskId, StartedAt = DateTime.UtcNow, Cts = cts };
+
+            _ = RunContinueInSlotAsync(taskId, followUpPrompt, cts.Token).ContinueWith(_ =>
+            {
+                lock (_lock) { _overrideSlot = null; }
+            }, TaskScheduler.Default);
+        }
+
+        return taskId;
+    }
+
     public bool CancelTask(string taskId)
     {
         lock (_lock)
@@ -159,4 +184,17 @@ public sealed class QueueService : BackgroundService
             _logger.LogError(ex, "Slot runner error for task {TaskId}", task.Id);
         }
     }
+
+    private async Task RunContinueInSlotAsync(string taskId, string followUpPrompt, CancellationToken ct)
+    {
+        try
+        {
+            _logger.LogInformation("Continuing task {TaskId} in override slot", taskId);
+            await _runner.ContinueAsync(taskId, followUpPrompt, "override", ct);
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "Continue runner error for task {TaskId}", taskId);
+        }
+    }
 }