PWA: Support offline use

[samouri]

summary

Numerous folks have reached out over email requesting the ability to install Sightread to use it while offline. This includes:

• Launching freeplay/learn a song mode while offline
• Having access the soundfont
• Playing builtin and locally synced/uploaded music

[benyamins]

I've tested the app with Tauri integration and it works pretty good! Detects MIDI and all that. Maybe that could be a better option? In the future Tauri will support IOS too.

[samouri]

@benyamins, that's pretty cool! Will investigate using Tauri when I have more time for it. If you have the code for the Tauri integration so that I can test it out, I'd love to see that