update node references in flows and memberships when nodes are merged

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

dante_control.go

@@ -80,6 +80,61 @@ func (d *DanteFlows) Update(source, subscriber *Node, channelInfo string) {
 	sub.LastSeen = time.Now()
 }
 
+func (d *DanteFlows) ReplaceNode(oldNode, newNode *Node) {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+
+	if flow, exists := d.flows[oldNode]; exists {
+		delete(d.flows, oldNode)
+		if existingFlow, hasNew := d.flows[newNode]; hasNew {
+			for subNode, sub := range flow.Subscribers {
+				if existingSub, hasSub := existingFlow.Subscribers[subNode]; hasSub {
+					for _, ch := range sub.Channels {
+						hasChannel := false
+						for _, existingCh := range existingSub.Channels {
+							if existingCh == ch {
+								hasChannel = true
+								break
+							}
+						}
+						if !hasChannel {
+							existingSub.Channels = append(existingSub.Channels, ch)
+						}
+					}
+				} else {
+					existingFlow.Subscribers[subNode] = sub
+				}
+			}
+		} else {
+			flow.Source = newNode
+			d.flows[newNode] = flow
+		}
+	}
+
+	for _, flow := range d.flows {
+		if sub, exists := flow.Subscribers[oldNode]; exists {
+			delete(flow.Subscribers, oldNode)
+			if existingSub, hasNew := flow.Subscribers[newNode]; hasNew {
+				for _, ch := range sub.Channels {
+					hasChannel := false
+					for _, existingCh := range existingSub.Channels {
+						if existingCh == ch {
+							hasChannel = true
+							break
+						}
+					}
+					if !hasChannel {
+						existingSub.Channels = append(existingSub.Channels, ch)
+					}
+				}
+			} else {
+				sub.Node = newNode
+				flow.Subscribers[newNode] = sub
+			}
+		}
+	}
+}
+
 func (d *DanteFlows) Expire() {
 	d.mu.Lock()
 	defer d.mu.Unlock()