FYI, it looks like raman325 has started working on adding Z-Wave SmartStart provisioning support to zwave_js WS API in Home Assistant core. Hopefully, that will also lead to frontend support later:
Also FYI; Z-Wave SmartStart QR scanning has been implemented in ZwaveJS2Mqtt’s as proof-of-concept, (feature in UI is however not named “Z-Wave SmartStart” but instead “Inclusion by QR Code”).
https://github.com/zwave-js/node-zwave-js/discussions/3381
https://github.com/zwave-js/zwavejs2mqtt/discussions
Again, please vote for related feature request asking for QR code tags scanning for joining devices: