This creates Unforget.app in ~/Applications which appears to work. I've also successfully used this with Tana in the past. Did you run into trouble with that or have you not tested it?
So, I was considering a PWA. I don't need tight local integration per se. I do have a conceptual problem not being able to save a file or read a file, even if it's just chosen by the user. I THINK I can do that. I THINK you can pop a file chooser to read a file, but not necessarily just open any file you want. If you can read/write a file as directed by a user, that would be fine. I can see the rest being stored in the IndexDB. And that gives the option of an export/backup if it becomes necessary for peace of mind.
Then there's the whole x-browser game, I'm not really looking at mobile, just desktop, but I'd like to support FF/Chrome/Safari/Edge.
It's not rocket science stuff by any means. But I don't want a user to call up and talking about how their data suddenly vanished because they went to get the latest, and I did something innocent/ignorant (or not), or THEY did something (deleted their PWA icon, copied it, moved it, etc.), or the browser did something.
I have no experience with it, so for now, I'm not comfortable because I don't have my "hands" on the data.
If I can export it, then the comfort level goes way up. Inform the user to back up "just in case", especially early on when we're all still bumping in the dark.
To be clear, I don't want a server side, I have no interest in standing up a service component. I have less interest in maintaining a service component. I'd like the code to be local and "standalone" as practical.
But I also want something a touch more than "git clone app; cd app; ./build".
I believe there are other libraries/frameworks on github with a similar approach you might want to have a look at.
Another similarity half-baked plan is for a PWA to regularly post (encrypted?) data to a service I'd host that simply forwards the data to the user's choice of cloud storage. It would require initial setup and probably regularly refreshing token, but should be workable.
Having said that, indexeddb has been very reliable. There are some annoying limitations though. For example, if you want to create an index on a store using multiple keys, you can't specify which key should be ascending or descending.
If you add the PWA to your home page, i.e. install it, then the browser must not clear indexeddb on an update or something. And as far as I can tell, browsers do respect that.
My overall experience building PWA has been mixed. I think it really depends on what app you're making. For a note taking app, where the data can be backed up to the cloud encrypted and synced, I really think a PWA is the best option. But if you want tighter integration with the platform e.g. accessing the file system, then I would stay away from PWA.
Another issue is ios safari which is missing a lot of features for PWAs and I think unlikely to support them in the future. E.g. background sync, offline push notifications, etc.
Are you considering PWA for any particular app?