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/offboard-spoke.sh

@@ -134,12 +134,8 @@ else
 fi
 
 header "Removing from Registry"
-if grep -v "^${SPOKE_NAME} " "$REGISTRY" > "${REGISTRY}.tmp" 2>/dev/null || true; then
-    mv "${REGISTRY}.tmp" "$REGISTRY"
-else
-    rm -f "${REGISTRY}.tmp"
-    die "Failed to update registry"
-fi
+grep -v "^${SPOKE_NAME} " "$REGISTRY" > "${REGISTRY}.tmp" 2>/dev/null || true
+mv "${REGISTRY}.tmp" "$REGISTRY"
 info "$SPOKE_NAME removed from registry."
 
 header "Offboarding Complete"