fix(canvas): 生成任务 - 校验视频提示词长度并修复工作流产物ID与供应商错误识别

backend/internal/service/project_workflow.go

@@ -1,6 +1,8 @@
 package service
 
 import (
+	"crypto/sha256"
+	"encoding/hex"
 	"encoding/json"
 	"errors"
 	"strings"
@@ -590,8 +592,8 @@ func (s *Service) ensureGeneratedProjectAsset(task model.Task, projectID string,
 		return "", err
 	}
 	now := time.Now()
-	assetID := "workflow-asset-" + task.ID
-	versionID := "workflow-version-" + task.ID
+	assetID := workflowGeneratedEntityID("asset", task.ID)
+	versionID := workflowGeneratedEntityID("version", task.ID)
 	label := "图片"
 	if mediaType == "video" {
 		label = "视频"
@@ -627,6 +629,12 @@ func (s *Service) ensureGeneratedProjectAsset(task model.Task, projectID string,
 	return versionID, nil
 }
 
+// 工作流产物重试必须复用同一实体 ID，同时需要满足素材版本及外键的 varchar(36) 约束。
+func workflowGeneratedEntityID(namespace string, taskID string) string {
+	sum := sha256.Sum256([]byte(strings.TrimSpace(namespace) + ":" + strings.TrimSpace(taskID)))
+	return hex.EncodeToString(sum[:16])
+}
+
 func validWorkflowStepStatus(status model.WorkflowStepStatus) bool {
 	switch status {
 	case model.WorkflowStepStatusPending, model.WorkflowStepStatusReady, model.WorkflowStepStatusRunning, model.WorkflowStepStatusReview, model.WorkflowStepStatusCompleted, model.WorkflowStepStatusFailed, model.WorkflowStepStatusSkipped: