waybar: add network widget, margins, border and rounded corners

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

config/waybar/network.sh

@@ -0,0 +1,35 @@
+#!/usr/bin/env bash
+CACHE="/tmp/waybar-net"
+iface=$(ip route get 8.8.8.8 2>/dev/null | awk '{for(i=1;i<=NF;i++) if($i=="dev") print $(i+1)}' | head -1)
+
+if [ -z "$iface" ]; then
+  echo "↑0B ↓0B"
+  exit 0
+fi
+
+rx=$(cat /sys/class/net/$iface/statistics/rx_bytes 2>/dev/null || echo 0)
+tx=$(cat /sys/class/net/$iface/statistics/tx_bytes 2>/dev/null || echo 0)
+now=$(date +%s%3N)
+
+if [ -f "$CACHE" ]; then
+  read -r prev_rx prev_tx prev_time < "$CACHE"
+  dt=$(( now - prev_time ))
+  [ "$dt" -le 0 ] && dt=1000
+  up=$(( (tx - prev_tx) * 1000 / dt ))
+  down=$(( (rx - prev_rx) * 1000 / dt ))
+else
+  up=0; down=0
+fi
+
+echo "$rx $tx $now" > "$CACHE"
+
+fmt() {
+  local b=$1
+  if   [ "$b" -ge 1073741824 ]; then printf "%4s" "$(( b / 1073741824 ))G"
+  elif [ "$b" -ge 1048576 ];    then printf "%4s" "$(( b / 1048576 ))M"
+  elif [ "$b" -ge 1024 ];       then printf "%4s" "$(( b / 1024 ))K"
+  else printf "%4s" "${b}B"
+  fi
+}
+
+echo "↑$(fmt "$up")/s ↓$(fmt "$down")/s"