setup-spoke.sh: fix port scan range and user@host sed regex, offboard/onboard-spoke.sh: fix registry grep-v empty-output clobber, setup-network.sh: fix wifi password colon handling

hub/setup-hub.sh

@@ -247,6 +247,7 @@ info "Checking SSH directory permissions..."
 check_permissions "$SSH_DIR/authorized_keys" "authorized_keys"
 check_permissions "$RCLONE_CONF" "rclone.conf"
 for PRIVKEY in "$SSH_DIR"/*; do
+    [ -e "$PRIVKEY" ] || continue
     [[ "$PRIVKEY" == *.pub ]] && continue
     [ -f "$PRIVKEY" ] || continue
     case "$(file -b "$PRIVKEY" 2>/dev/null)" in