sprint 4 adds gpu support

README.md

@@ -8,6 +8,7 @@
 - Sortable process columns (PID/CPU/MEM) with direction indicators
 - Toggleable process details pane (right on wide terminals, bottom on narrow)
 - CPU total bar + per-core mini-bars
+- GPU widget (NVIDIA via `nvidia-smi`, AMD via Linux sysfs when available)
 - Memory/swap bars and disk usage bars (top-N by usage)
 - Disk pseudo-filesystem filtering toggle (`tmpfs`/`devtmpfs`/`overlay`)
 - Compact network rates + totals + interface label
@@ -58,6 +59,7 @@ Accepted interval range: `200..=5000` ms.
 - Target platform is Linux.
 - Network throughput is computed as a delta between consecutive samples.
 - Disk and network metrics are system-wide aggregates.
+- GPU metrics are best-effort: NVIDIA requires `nvidia-smi`; AMD uses available `/sys/class/drm` fields.
 
 ## Next steps