Improve workers for backtests

src/Managing.Application/Backtests/BacktestJobService.cs

@@ -250,5 +250,58 @@ public class JobService
             throw;
         }
     }
+
+    /// <summary>
+    /// Retries a failed or cancelled job by resetting it to Pending status.
+    /// </summary>
+    /// <param name="jobId">The job ID to retry</param>
+    /// <returns>The updated job</returns>
+    /// <exception cref="InvalidOperationException">Thrown if job cannot be retried</exception>
+    public async Task<Job> RetryJobAsync(Guid jobId)
+    {
+        var job = await _jobRepository.GetByIdAsync(jobId);
+        
+        if (job == null)
+        {
+            throw new InvalidOperationException($"Job with ID {jobId} not found.");
+        }
+
+        // Only allow retrying Failed or Cancelled jobs
+        // Running jobs should be handled by stale job recovery, not manual retry
+        if (job.Status != JobStatus.Failed && job.Status != JobStatus.Cancelled)
+        {
+            throw new InvalidOperationException($"Cannot retry job with status {job.Status}. Only Failed or Cancelled jobs can be retried.");
+        }
+
+        // Reset job to pending state
+        job.Status = JobStatus.Pending;
+        job.AssignedWorkerId = null;
+        job.LastHeartbeat = null;
+        job.StartedAt = null;
+        job.CompletedAt = null;
+        job.ProgressPercentage = 0;
+        job.RetryAfter = null;
+        // Keep ErrorMessage for reference, but clear it on next run
+        // Keep RetryCount to track total retries
+        // Reset IsRetryable to true
+        job.IsRetryable = true;
+
+        await _jobRepository.UpdateAsync(job);
+
+        _logger.LogInformation("Job {JobId} reset to Pending status for retry", jobId);
+
+        return job;
+    }
+
+    /// <summary>
+    /// Deletes a job from the database.
+    /// </summary>
+    /// <param name="jobId">The job ID to delete</param>
+    /// <exception cref="InvalidOperationException">Thrown if job cannot be found</exception>
+    public async Task DeleteJobAsync(Guid jobId)
+    {
+        await _jobRepository.DeleteAsync(jobId);
+        _logger.LogInformation("Deleted job {JobId}", jobId);
+    }
 }