fix: make sure new nodes are reactive

Closes #7

app/src/lib/graph-interface/graph-manager.svelte.ts

@@ -178,7 +178,6 @@ export class GraphManager extends EventEmitter<{
         const nodeType = this.registry.getNode(node.type);
         if (nodeType) {
           node.tmp = {
-            random: (Math.random() - 0.5) * 2,
             type: nodeType,
           };
         }
@@ -234,7 +233,6 @@ export class GraphManager extends EventEmitter<{
         return;
       }
       node.tmp = node.tmp || {};
-      node.tmp.random = (Math.random() - 0.5) * 2;
       node.tmp.type = nodeType;
     }
 
@@ -460,13 +458,13 @@ export class GraphManager extends EventEmitter<{
       return;
     }
 
-    const node: Node = {
+    const node: Node = $state({
       id: this.createNodeId(),
       type,
       position,
       tmp: { type: nodeType },
       props,
-    };
+    });
 
     this.nodes.set(node.id, node);