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_agent/internal/state/state.go

@@ -20,6 +20,7 @@ type Snapshot struct {
 	LastCPUStatTotal       uint64 `json:"last_cpu_stat_total"`
 	LastCPUStatIdle        uint64 `json:"last_cpu_stat_idle"`
 	LastMetricAtUnix       int64  `json:"last_metric_at_unix"`
+	AccessLogOffset        int64  `json:"access_log_offset"`
 }
 
 type Store struct {