fix(netconf): accept interface number as input, not just name

User sees a numbered list but could only type the name.
Now numeric input is resolved to the interface name via awk NR==N.

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

iso/overlay/usr/local/bin/netconf

@@ -13,11 +13,22 @@ for iface in $IFACES; do
     i=$((i+1))
 done
 echo ""
-printf "Interface name [or Enter to pick first]: "
+printf "Interface number or name [Enter = first]: "
-read IFACE
+read INPUT
-if [ -z "$IFACE" ]; then
+
+if [ -z "$INPUT" ]; then
     IFACE=$(echo "$IFACES" | head -1)
+elif echo "$INPUT" | grep -qE '^[0-9]+$'; then
+    # Numeric input — resolve to name
+    IFACE=$(echo "$IFACES" | awk "NR==$INPUT")
+    if [ -z "$IFACE" ]; then
+        echo "Error: no interface with number $INPUT"
+        exit 1
     fi
+else
+    IFACE="$INPUT"
+fi
+
 echo "Selected: $IFACE"
 echo ""
 echo "  1) DHCP"