[BUG] Memory leak in PanningManager: some listeners are not destroyed
Memory leak in PanningManager due to missing cleanup of mouseUpListener after graph destruction.
Environment:"@maxgraph/core": "^0.22.0"
Code location: PanningManager.js this.mouseUpListener = () => { if (this.active) this.stop(); };
this.mouseUpListener = () => { if (this.active) this.stop(); };