feat: add 24-hour traffic and capacity trend charts to dashboard and node detail pages

- Implemented TrendChart component for visualizing traffic and capacity trends.
- Enhanced DashboardOverview and NodeDetailPage components to display 24-hour request and capacity trends.
- Updated types to include traffic and capacity trend data structures.
- Created observability trends service to aggregate traffic and capacity data.
- Added tests for traffic report generation and trend data handling.
- Introduced new dependencies for charting (echarts and echarts-for-react).

atsf_server/service/node_observability.go

@@ -25,16 +25,23 @@ type NodeObservabilityView struct {
 	MetricSnapshots []*model.NodeMetricSnapshot `json:"metric_snapshots"`
 	TrafficReports  []*model.NodeRequestReport  `json:"traffic_reports"`
 	HealthEvents    []*model.NodeHealthEvent    `json:"health_events"`
+	Trends          NodeObservabilityTrends     `json:"trends"`
+}
+
+type NodeObservabilityTrends struct {
+	Traffic24h  []TrafficTrendPoint  `json:"traffic_24h"`
+	Capacity24h []CapacityTrendPoint `json:"capacity_24h"`
 }
 
 func GetNodeObservability(id uint, query NodeObservabilityQuery) (*NodeObservabilityView, error) {
+	now := time.Now()
 	node, err := model.GetNodeByID(id)
 	if err != nil {
 		return nil, err
 	}
 
 	limit := normalizeObservabilityLimit(query.Limit)
-	since := time.Now().Add(-normalizeObservabilityWindow(query.Hours))
+	since := now.Add(-normalizeObservabilityWindow(query.Hours))
 
 	profile, err := model.GetNodeSystemProfile(node.NodeID)
 	if err != nil && !errors.Is(err, gorm.ErrRecordNotFound) {
@@ -52,6 +59,14 @@ func GetNodeObservability(id uint, query NodeObservabilityQuery) (*NodeObservabi
 	if err != nil {
 		return nil, err
 	}
+	trendSnapshots, err := model.ListNodeMetricSnapshots(node.NodeID, now.Add(-24*time.Hour), 0)
+	if err != nil {
+		return nil, err
+	}
+	trendReports, err := model.ListNodeRequestReports(node.NodeID, now.Add(-24*time.Hour), 0)
+	if err != nil {
+		return nil, err
+	}
 	events, err := model.ListNodeHealthEvents(node.NodeID, false, limit)
 	if err != nil {
 		return nil, err
@@ -63,6 +78,10 @@ func GetNodeObservability(id uint, query NodeObservabilityQuery) (*NodeObservabi
 		MetricSnapshots: snapshots,
 		TrafficReports:  reports,
 		HealthEvents:    events,
+		Trends: NodeObservabilityTrends{
+			Traffic24h:  buildTrafficTrendPoints(now, trendReports),
+			Capacity24h: buildCapacityTrendPoints(now, trendSnapshots),
+		},
 	}, nil
 }