Fix High Ping & Jitter (Lag Spikes, Packet Loss)

Step-by-step fixes

1. Test latency and jitter
   Test latency and jitter – Measure baseline ping/jitter, then compare after each change.
2. Switch to Ethernet
   Switch to Ethernet – Wired connections reduce jitter and packet loss dramatically.
3. Reboot modem/router
   Reboot modem/router – Power cycle for 30 seconds to clear instability.
4. Change Wi‑Fi band/channel
   Change Wi‑Fi band/channel – Use 5GHz, move closer to router, avoid crowded channels.
5. Stop heavy uploads
   Stop heavy uploads – Cloud backups and uploads can cause bufferbloat and lag spikes.