Figure out how to give better feedback on Next.js server forms when we do not navigate after submit

[japsu]

Single response view, dimensions form: The form autosubmits unless JavaScript is disabled. There could be some message stating changes have been saved.

Survey editor view, survey / language version settings forms: There is a SubmitButton. We stay in the same view after saving.

[Aketzu]

Material Design uses snackbars https://m3.material.io/components/snackbar/guidelines which can be done with https://getbootstrap.com/docs/5.3/components/toasts/

Could also be spinner next to element while data is being saved (but at least one second) https://getbootstrap.com/docs/5.3/components/spinners/