Node Flickering and Unstable Graph Layout

The network map nodes exhibit significant jitter, flickering, and continuous movement even when no new devices are being discovered. Instead of settling into a clean, organic structure, the nodes "bounce" off the edges or vibrate rapidly in place.

Steps to Reproduce
- Launch Termi-Graph.
- Wait for ARP discovery to find 2+ nodes.
- Observe the nodes vibrating or flying off-screen.