Instead of having to define what “local-first” means to you personally you should emphasize that the data lives on your local machine. For some example messaging take a look at how Apple is marketing their new Siri AI.
That's fair - "your data lives on your machine as plain files" is the concrete claim, and something we should lead with. Will take a look at how Apple frames it, thanks.
You have completely misused and re-purposed this term. The common interpretation is that the software will continue to function without an internet connection which is not the case for your product.