fix(lint): 修复代码格式和未使用变量问题

- 修复 ops_ws_handler.go 中的代码格式和返回值
- 移除 ops_repo_latency_histogram_buckets.go 中不必要的错误检查
- 修复 api_contract_test.go 缩进并添加运维监控配置项测试
- 移除 ops_cleanup_service.go 中未使用的变量
- 添加 ops_retry.go 中缺失的 status 字段

backend/internal/handler/admin/ops_ws_handler.go

@@ -391,7 +391,10 @@ func tryAcquireOpsWSIPSlot(clientIP string, limit int32) bool {
 	}
 
 	v, _ := wsConnCountByIP.LoadOrStore(clientIP, &atomic.Int32{})
-	counter, ok := v.(*atomic.Int32); if !ok { return }
+	counter, ok := v.(*atomic.Int32)
+	if !ok {
+		return false
+	}
 
 	for {
 		current := counter.Load()

backend/internal/repository/ops_repo_latency_histogram_buckets.go

@@ -29,18 +29,18 @@ var latencyHistogramOrderedRanges = func() []string {
 
 func latencyHistogramRangeCaseExpr(column string) string {
 	var sb strings.Builder
-	_ = sb.WriteString("CASE\n")
+	sb.WriteString("CASE\n")
 
 	for _, b := range latencyHistogramBuckets {
 		if b.upperMs <= 0 {
 			continue
 		}
-		_ = sb.WriteString(fmt.Sprintf("\tWHEN %s < %d THEN '%s'\n", column, b.upperMs, b.label))
+		sb.WriteString(fmt.Sprintf("\tWHEN %s < %d THEN '%s'\n", column, b.upperMs, b.label))
 	}
 
 	// Default bucket.
 	last := latencyHistogramBuckets[len(latencyHistogramBuckets)-1]
-	_ = sb.WriteString(fmt.Sprintf("\tELSE '%s'\n", last.label))
+	sb.WriteString(fmt.Sprintf("\tELSE '%s'\n", last.label))
 	sb.WriteString("END")
 	return sb.String()
 }

backend/internal/server/api_contract_test.go

@@ -287,6 +287,11 @@ func TestAPIContracts(t *testing.T) {
 
 						service.SettingKeyDefaultConcurrency: "5",
 						service.SettingKeyDefaultBalance:     "1.25",
+
+						service.SettingKeyOpsMonitoringEnabled:         "false",
+						service.SettingKeyOpsRealtimeMonitoringEnabled: "true",
+						service.SettingKeyOpsQueryModeDefault:          "auto",
+						service.SettingKeyOpsMetricsIntervalSeconds:    "60",
 					})
 				},
 			method:     http.MethodGet,
@@ -312,6 +317,10 @@ func TestAPIContracts(t *testing.T) {
 						"linuxdo_connect_client_id": "",
 						"linuxdo_connect_client_secret_configured": false,
 						"linuxdo_connect_redirect_url": "",
+						"ops_monitoring_enabled": false,
+						"ops_realtime_monitoring_enabled": true,
+						"ops_query_mode_default": "auto",
+						"ops_metrics_interval_seconds": 60,
 						"site_name": "Sub2API",
 						"site_logo": "",
 						"site_subtitle": "Subtitle",

backend/internal/service/ops_cleanup_service.go

@@ -97,17 +97,16 @@ func (s *OpsCleanupService) Start() {
 			}
 	
 			c := cron.New(cron.WithParser(opsCleanupCronParser), cron.WithLocation(loc))
-		id, err := c.AddFunc(schedule, func() { s.runScheduled() })
+			_, err := c.AddFunc(schedule, func() { s.runScheduled() })
 			if err != nil {
 				log.Printf("[OpsCleanup] not started (invalid schedule=%q): %v", schedule, err)
 				return
 			}
 			s.cron = c
-		s.entryID = id
 			s.cron.Start()
 			log.Printf("[OpsCleanup] started (schedule=%q tz=%s)", schedule, loc.String())
 		})
-}
+	}
 
 func (s *OpsCleanupService) Stop() {
 	if s == nil {

backend/internal/service/ops_retry.go

@@ -52,6 +52,7 @@ const (
 type limitedResponseWriter struct {
 	header      http.Header
 	wroteHeader bool
+	status      int
 
 	limit        int
 	totalWritten int64