Skybook — iPad sign-in spike
Throwaway. Answers one question: does OAuth survive an installed home-screen app, and does the token land in the container the app can read? Nothing here is Skybook code.
1 · Where am I running
2 · Storage — is it retained, or just cache?
Roughly a pilot photo, a few aircraft photos and a signature — the shape of data Skybook actually keeps. Write it, force-close the app, relaunch, and check it is still here.
3 · Files — the backup tier
Browser storage dies if the home-screen icon is deleted. This is the tier that doesn't: a real document in the Files app. This is a backup, not the live data store — iOS gives a web app no way to write to a chosen file repeatedly, so the app cannot run from here. Export, and check whether iOS offered you Save to Files.
4 · Sign in — two routes, deliberately
These differ in a way that may matter on iOS: one navigates straight to another origin, the other navigates to this origin and gets redirected. Try both, note which returns.