feat: 工单审批流程支持 workflow 指定用户审批 + Redis 命令执行

1. 工单创建时读取 workflow_steps 的 approver_ids 创建审批记录
   - 有指定用户：为每个用户创建审批记录（任一通过即可）
   - 无指定用户：按 approver_role 角色匹配 fallback
   - 无 workflow：默认 admin 审批
2. Redis 工单执行：复用 getRedisClient + parseCommandParts 执行写命令
   - 支持 SET/DEL/HSET 等所有写操作
   - 解析 db0/db1 格式的目标库
   - 返回 [OK] 命令 → 结果

backend/internal/handler/ticket.go

@@ -1,6 +1,7 @@
 package handler
 
 import (
+	"context"
 	"encoding/json"
 	"fmt"
 	"net/http"
@@ -211,23 +212,76 @@ func CreateTicket(c *gin.Context) {
 		return
 	}
 	
-	// Auto-create approval record: step 1, approver = instance owner or admin
-	stepName := "审核"
-	stepType := "audit"
-	approverRole := "admin"
-	// Find first admin as default approver
-	var adminUser model.User
-	if err := model.DB.Where("role = ? AND is_active = 1", "admin").First(&adminUser).Error; err == nil {
-		adminID := adminUser.ID
-		approval := model.TicketApproval{
-			TicketID:    ticket.ID,
-			StepNumber:  1,
-			StepName:    &stepName,
-			StepType:    &stepType,
-			ApproverID:  &adminID,
-			ApproverRole: &approverRole,
+	// Create approval records based on workflow or default to admin
+	if input.WorkflowID != nil && *input.WorkflowID > 0 {
+		// Load workflow steps
+		var wfSteps []model.WorkflowStep
+		model.DB.Where("workflow_id = ?", *input.WorkflowID).Order("step_number").Find(&wfSteps)
+		for _, ws := range wfSteps {
+			if ws.StepType == "submit" {
+				continue // submit step needs no approver
+			}
+			// Parse approver_ids from JSON
+			var approverIDs []int
+			if ws.ApproverIDs != nil && *ws.ApproverIDs != "" {
+				json.Unmarshal([]byte(*ws.ApproverIDs), &approverIDs)
+			}
+			// Create one approval record per approver (any one can approve)
+			if len(approverIDs) > 0 {
+				for _, uid := range approverIDs {
+					uidCopy := uid
+					stepName := ws.Name
+					stepType := ws.StepType
+					approval := model.TicketApproval{
+						TicketID:    ticket.ID,
+						StepNumber:  ws.StepNumber,
+						StepName:    &stepName,
+						StepType:    &stepType,
+						ApproverID:  &uidCopy,
+					}
+					model.DB.Create(&approval)
+				}
+			} else {
+				// No specific users — use role-based fallback
+				stepName := ws.Name
+				stepType := ws.StepType
+				var roleUser model.User
+				role := "admin"
+				if ws.ApproverRole != nil && *ws.ApproverRole != "" {
+					role = *ws.ApproverRole
+				}
+				if model.DB.Where("role = ? AND is_active = 1", role).First(&roleUser).Error == nil {
+					rid := roleUser.ID
+					approval := model.TicketApproval{
+						TicketID:     ticket.ID,
+						StepNumber:   ws.StepNumber,
+						StepName:     &stepName,
+						StepType:     &stepType,
+						ApproverID:   &rid,
+						ApproverRole: &role,
+					}
+					model.DB.Create(&approval)
+				}
+			}
+		}
+	} else {
+		// No workflow — default: first admin as approver
+		stepName := "审核"
+		stepType := "audit"
+		approverRole := "admin"
+		var adminUser model.User
+		if err := model.DB.Where("role = ? AND is_active = 1", "admin").First(&adminUser).Error; err == nil {
+			adminID := adminUser.ID
+			approval := model.TicketApproval{
+				TicketID:     ticket.ID,
+				StepNumber:   1,
+				StepName:     &stepName,
+				StepType:     &stepType,
+				ApproverID:   &adminID,
+				ApproverRole: &approverRole,
+			}
+			model.DB.Create(&approval)
 		}
-		model.DB.Create(&approval)
 	}
 	
 	c.JSON(http.StatusCreated, ticket)
@@ -339,7 +393,36 @@ func ExecuteTicket(c *gin.Context) {
 	var execErr string
 	
 	if ticket.DBType == "redis" {
-		execErr = "Redis command execution not yet supported in ticket workflow"
+		// Execute Redis command (write operations allowed in ticket workflow)
+		redisDB := 0
+		if ticket.TargetDatabase != "" {
+			if n, err := strconv.Atoi(strings.TrimPrefix(ticket.TargetDatabase, "db")); err == nil && n >= 0 {
+				redisDB = n
+			}
+		}
+		client, err := getRedisClient(&instance, redisDB)
+		if err != nil {
+			execErr = fmt.Sprintf("Redis connection failed: %v", err)
+		} else {
+			defer client.Close()
+			ctx := context.Background()
+			parts := parseCommandParts(ticket.SQLContent)
+			if len(parts) == 0 {
+				execErr = "empty command"
+			} else {
+				cmd := strings.ToUpper(parts[0])
+				args := make([]interface{}, len(parts))
+				for i, p := range parts {
+					args[i] = p
+				}
+				result, err := client.Do(ctx, args...).Result()
+				if err != nil {
+					execErr = fmt.Sprintf("%s failed: %v", cmd, err)
+				} else {
+					execResult = fmt.Sprintf("[OK] %s → %v", ticket.SQLContent, result)
+				}
+			}
+		}
 	} else {
 		// MySQL/PG execution
 		db, err := getDBConnection(&instance, ticket.TargetDatabase)