fix(monitor): add tunnel quality detection toggle

Allow admins to disable real-time tunnel quality probing from settings so the monitor UI and backend probe loop stop together.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

go-backend/internal/http/handler/handler.go

@@ -46,6 +46,8 @@ type Handler struct {
 	qualityProber *tunnelQualityProber
 }
 
+const monitorTunnelQualityEnabledConfigKey = "monitor_tunnel_quality_enabled"
+
 type loginRequest struct {
 	Username  string `json:"username"`
 	Password  string `json:"password"`
@@ -886,11 +888,32 @@ func normalizeAndValidateConfigValue(key, value string) (string, error) {
 		}
 
 		return pngDataURLPrefix + payload, nil
+	case monitorTunnelQualityEnabledConfigKey:
+		normalized := strings.TrimSpace(strings.ToLower(value))
+		switch normalized {
+		case "true", "false":
+			return normalized, nil
+		default:
+			return "", fmt.Errorf("隧道质量检测开关配置值无效")
+		}
 	default:
 		return value, nil
 	}
 }
 
+func (h *Handler) isTunnelQualityMonitoringEnabled() bool {
+	if h == nil || h.repo == nil {
+		return true
+	}
+
+	cfg, err := h.repo.GetConfigByName(monitorTunnelQualityEnabledConfigKey)
+	if err != nil || cfg == nil {
+		return true
+	}
+
+	return strings.TrimSpace(strings.ToLower(cfg.Value)) != "false"
+}
+
 func (h *Handler) userPackage(w http.ResponseWriter, r *http.Request) {
 	if r.Method != http.MethodPost {
 		response.WriteJSON(w, response.ErrDefault("请求失败"))

go-backend/internal/http/handler/jobs.go

@@ -66,9 +66,11 @@ func (h *Handler) runHealthChecks(ctx context.Context) {
 
 func (h *Handler) runTunnelQualityProber(ctx context.Context) {
 	defer h.jobsWG.Done()
-	if h.qualityProber != nil {
-		h.qualityProber.Start(ctx)
+	if h == nil || h.qualityProber == nil || !h.isTunnelQualityMonitoringEnabled() {
+		return
 	}
+
+	h.qualityProber.Start(ctx)
 }
 
 func (h *Handler) runHourlyStatsLoop(ctx context.Context) {

go-backend/internal/http/handler/tunnel_quality_prober.go

@@ -48,11 +48,8 @@ type tunnelQualityProber struct {
 
 // newTunnelQualityProber creates a new prober (not yet running).
 func newTunnelQualityProber(h *Handler) *tunnelQualityProber {
-	ctx, cancel := context.WithCancel(context.Background())
 	return &tunnelQualityProber{
 		handler:  h,
-		ctx:      ctx,
-		cancel:   cancel,
 		interval: tunnelQualityProbeInterval,
 	}
 }
@@ -66,6 +63,10 @@ func (p *tunnelQualityProber) Start(ctx context.Context) {
 
 // Stop halts the background probe loop.
 func (p *tunnelQualityProber) Stop() {
+	if p == nil || p.cancel == nil {
+		return
+	}
+
 	p.cancel()
 }
 
@@ -106,8 +107,20 @@ func (p *tunnelQualityProber) loop() {
 	}
 }
 
+func (p *tunnelQualityProber) isEnabled() bool {
+	if p == nil || p.handler == nil {
+		return true
+	}
+
+	return p.handler.isTunnelQualityMonitoringEnabled()
+}
+
 // maybePrune deletes old quality rows periodically (mirrors PruneServiceMonitorResults).
 func (p *tunnelQualityProber) maybePrune() {
+	if !p.isEnabled() {
+		return
+	}
+
 	now := time.Now().UnixMilli()
 	if p.lastPrune > 0 && now-p.lastPrune < int64(tunnelQualityPruneInterval/time.Millisecond) {
 		return
@@ -126,6 +139,10 @@ func (p *tunnelQualityProber) maybePrune() {
 }
 
 func (p *tunnelQualityProber) probeAll() {
+	if !p.isEnabled() {
+		return
+	}
+
 	// Skip if previous probe round is still running (interval < timeout guard)
 	if !atomic.CompareAndSwapInt32(&p.probing, 0, 1) {
 		return