feat(flow): 实时全链路流程可视化 P1——trace→graph_update→前端全链路流程页(design/19)

后端: trace/graph.go(RunGraph 图构建器,kind/status 映射,父子优先连线,脱敏白名单+截断);
       loop/flow.go(FlowPublisher 按会话增量发布 ws.graph_update,仅主人web会话); loop span
       start/finish 折入图; run.go StartRound/EndRound; wire.go 组装+注入.
前端: Flow.tsx(全链路流程页:FlowGraphView+会话/节点/开始/耗时卡片+状态计数+节点点开日志);
       FlowGraph 组件加 onNodeClick; types/wsParse 扩展; router/sections/AdminApp 注册 flow;
       api-client.md §3.5 graph_update 契约.
验证: 后端 build/vet/test 全绿+flow_test.go 集成(span→graph→ws.graph_update主干); 前端 build 绿.
红线: 单二进制零新依赖; 工具参数/结果脱敏; 仅主人web会话; 身份靠actor元数据; 只读不虚构.
P2(并行子代理分支/泳道/节点实时日志)后置.

internal/runtime/loop/run.go

@@ -49,6 +49,10 @@ func (l *Loop) Run(ctx context.Context, sessionID string, messages []model.Messa
 	msgs = l.resolveImages(ctx, msgs)
 	toolState := &toolLoopState{prevFP: make(map[string]bool)}
 	res := &Result{}
+	if l.flow != nil {
+		l.flow.StartRound(sessionID, lastUserText(msgs))
+		defer func() { l.flow.EndRound(sessionID, res.Text) }()
+	}
 	for step := startStep; step <= l.maxRounds; step++ {
 		if err := ctx.Err(); err != nil {
 			return nil, fmt.Errorf("loop: run: step %d: %w", step, err)