fix(lint): 修复所有golangci-lint错误

- 修复depguard错误：为ops service文件添加redis导入例外
- 修复errcheck错误：添加错误检查和类型断言检查
- 修复gofmt错误：格式化代码
- 修复ineffassign错误：移除无效的idx++赋值
- 修复staticcheck错误：合并条件赋值
- 修复unused错误：移除未使用的字段和函数
  - ops_cleanup_service.go: entryID字段
  - ops_retry.go: status字段
  - ops_upstream_context.go: getOpsUpstreamErrors函数

backend/internal/service/ops_cleanup_service.go

@@ -44,8 +44,7 @@ type OpsCleanupService struct {
 
 	instanceID string
 
-	cron    *cron.Cron
-	entryID cron.EntryID
+	cron *cron.Cron
 
 	startOnce sync.Once
 	stopOnce  sync.Once

backend/internal/service/ops_retry.go

@@ -51,7 +51,6 @@ const (
 
 type limitedResponseWriter struct {
 	header      http.Header
-	status      int
 	wroteHeader bool
 
 	limit        int

backend/internal/service/ops_scheduled_report_service.go

@@ -62,10 +62,7 @@ func NewOpsScheduledReportService(
 	redisClient *redis.Client,
 	cfg *config.Config,
 ) *OpsScheduledReportService {
-	lockOn := true
-	if cfg != nil && strings.TrimSpace(cfg.RunMode) == config.RunModeSimple {
-		lockOn = false
-	}
+	lockOn := cfg == nil || strings.TrimSpace(cfg.RunMode) != config.RunModeSimple
 
 	loc := time.Local
 	if cfg != nil && strings.TrimSpace(cfg.Timezone) != "" {

backend/internal/service/ops_upstream_context.go

@@ -80,18 +80,6 @@ func appendOpsUpstreamError(c *gin.Context, ev OpsUpstreamErrorEvent) {
 	c.Set(OpsUpstreamErrorsKey, existing)
 }
 
-func getOpsUpstreamErrors(c *gin.Context) []*OpsUpstreamErrorEvent {
-	if c == nil {
-		return nil
-	}
-	if v, ok := c.Get(OpsUpstreamErrorsKey); ok {
-		if arr, ok := v.([]*OpsUpstreamErrorEvent); ok {
-			return arr
-		}
-	}
-	return nil
-}
-
 func marshalOpsUpstreamErrors(events []*OpsUpstreamErrorEvent) *string {
 	if len(events) == 0 {
 		return nil