Title a collapsed Variables or Properties node by what it does

Collapsed, the node reads "Set 2 variables", "Get width" or "No properties";
expanded it is always "Variables" / "Properties". The Properties node shows
its object type (and behavior) as a line under the title instead.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/core/graph/nodes/variable/Variables.ts

@@ -1,4 +1,4 @@
-import { portDefOf, VARIABLES } from '../../nested';
+import { collapsedTitle, portDefOf, VARIABLES } from '../../nested';
 import { type NodeDef, withInlineDefault } from '../../NodeRegistry';
 import { writeTyped } from '../../values';
 import { exec } from '../shared';
@@ -21,9 +21,8 @@ export const Variables: NodeDef = {
   declaredPort: (port) => withInlineDefault(portDefOf(port)),
   derivePorts: ({ node }) => {
     const ports = node.ports ?? [];
-    const only = ports.length === 1 ? ports[0]?.key : undefined;
     const shape = ports.some((p) => p.write) ? { inputs: [exec()], outputs: [exec()] } : {};
-    return only ? { ...shape, label: only } : shape;
+    return node.collapsed ? { ...shape, label: collapsedTitle(ports, 'variables') } : shape;
   },
   read: (ctx) => ctx.variables,
   run: (ctx, inputs, _params, def) => {