fix: remove CRDT observer feedback loop causing drag issues

The Yjs map observers were calling notifyNodesChange/notifyEdgesChange
for local changes, creating a feedback loop that reset React Flow state
mid-drag. Remote notifications are already handled by the connectChannel
handler, so the observers only need to schedule persistence.

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

src/lib/collaboration/crdt.ts

@@ -27,16 +27,14 @@ export class CRDTManager {
     this.edgesMap = this.doc.getMap('edges')
     this.callbacks = callbacks
 
-    // Listen for remote Yjs document changes
+    // Schedule persistence on local Yjs document changes
     this.nodesMap.observe(() => {
       if (this.isApplyingRemote) return
-      this.notifyNodesChange()
       this.schedulePersist()
     })
 
     this.edgesMap.observe(() => {
       if (this.isApplyingRemote) return
-      this.notifyEdgesChange()
       this.schedulePersist()
     })