feat: expose workflow state events and persist signal transitions

sdk/go/examples/workflow/main.go

@@ -189,6 +189,39 @@ func run() error {
 		return errors.New("signal history missing")
 	}
 	fmt.Println("workflow_history_verified=true signal_state=CONSUMED")
+	// 时间线用于审计展示，游标只是倒序翻页位置，不作为可靠消息消费水位。
+	cursor, eventCount, consumed := "", 0, false
+	for {
+		page, err := client.ListWorkflowEvents(ctx, accepted.Instance.ID, orbit.HistoryPageRequest{Limit: 5, Cursor: cursor})
+		if err != nil {
+			return err
+		}
+		for _, event := range page.Items {
+			eventCount++
+			if event.AggregateKind == "workflow_signal" && event.AggregateID == sent.Signal.ID && event.State == "CONSUMED" {
+				detail, err := client.GetWorkflowEvent(ctx, accepted.Instance.ID, event.ID)
+				if err != nil {
+					return err
+				}
+				var transition struct {
+					From           string `json:"from"`
+					ConsumedWaitID string `json:"consumed_wait_id"`
+				}
+				if json.Unmarshal(detail.Payload, &transition) != nil || transition.From != "PENDING" || transition.ConsumedWaitID != historical.Wait.ID {
+					return errors.New("signal transition evidence mismatch")
+				}
+				consumed = true
+			}
+		}
+		if page.NextCursor == "" {
+			break
+		}
+		cursor = page.NextCursor
+	}
+	if !consumed {
+		return errors.New("consumed signal event missing")
+	}
+	fmt.Printf("workflow_timeline_verified=true events=%d signal_transition=PENDING->CONSUMED\n", eventCount)
 
 	stop()
 	err = <-done