feat(webhook): add workflow_step webhook events for step-level CI notifications

Adds HookEventWorkflowStep event type that fires on every step state
transition (queued -> in_progress -> completed). Follows the same
pattern as the existing workflow_job events.

- New WorkflowStepPayload struct with run/job/step context
- WorkflowStepStatusUpdate notifier interface + dispatch
- Step state change detection in UpdateTask runner endpoint
- Fix: register workflow_step in updateHookEvents API mapping
- Full test coverage mirroring workflow_job tests

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

services/webhook/general.go

@@ -389,6 +389,37 @@ func getWorkflowJobPayloadInfo(p *api.WorkflowJobPayload, linkFormatter linkForm
 	return text, color
 }
 
+func getWorkflowStepPayloadInfo(p *api.WorkflowStepPayload, linkFormatter linkFormatter, withSender bool) (text string, color int) {
+	description := p.Step.Conclusion
+	if description == "" {
+		description = p.Step.Status
+	}
+	stepLink := linkFormatter(p.WorkflowJob.HTMLURL, fmt.Sprintf("%s / %s", p.WorkflowJob.Name, p.Step.Name)+":"+description)
+
+	text = fmt.Sprintf("Workflow Step %s: %s", p.Action, stepLink)
+	switch description {
+	case "waiting":
+		color = orangeColor
+	case "queued":
+		color = orangeColorLight
+	case "success":
+		color = greenColor
+	case "failure":
+		color = redColor
+	case "cancelled":
+		color = yellowColor
+	case "skipped":
+		color = purpleColor
+	default:
+		color = greyColor
+	}
+	if withSender {
+		text += " by " + linkFormatter(setting.AppURL+url.PathEscape(p.Sender.UserName), p.Sender.UserName)
+	}
+
+	return text, color
+}
+
 // ToHook convert models.Webhook to api.Hook
 // This function is not part of the convert package to prevent an import cycle
 func ToHook(repoLink string, w *webhook_model.Webhook) (*api.Hook, error) {