feat(obs): 访问日志 SSOT 与 edge_health，去掉协议兼容层

Agent 仅上报 host_metrics/edge_health/access_logs；业务流量与 UV 由
Server 侧访问日志聚合。新增 of_node_edge_health 与 of_access_log_hourly，
删除 request_reports/openresty 吞吐路径；API 不再暴露 traffic_reports
与 openresty_rx|tx。心跳/离线默认阈值与回填迁移一并入库。

internal/apps/openflare/relay/helpers.go

@@ -16,7 +16,7 @@ const (
 	relayStatusUnhealthy = "unhealthy"
 	releaseChannelStable = "stable"
 
-	defaultAgentHeartbeatInterval = 10000 // 默认心跳间隔 10 秒（毫秒）
+	defaultAgentHeartbeatInterval = 3000 // 默认心跳间隔 3 秒（毫秒）
 	defaultAgentUpdateRepo        = "Rain-kl/OpenFlare"
 )
 

internal/apps/openflare/relay/observability.go

@@ -47,7 +47,7 @@ func reconcileRelayHealthEvents(ctx context.Context, nodeID string, relayStatus
 func persistRelayHeartbeatObservability(ctx context.Context, nodeID string, payload HeartbeatPayload, reportedAt time.Time) {
 	agent.PersistHeartbeatObservability(ctx, nodeID, agent.NodePayload{
 		Profile:      payload.Profile,
-		Snapshot:     payload.Snapshot,
+		HostMetrics:  payload.Snapshot,
 		HealthEvents: payload.HealthEvents,
 	}, reportedAt)