Export might need better guidance for Android or to eventually use Share APIs

[NoelLH]

There's little control over where exports go with the current method, although I think it should be in a user-accessible Documents folder on modern Androids.

I haven't been able to try it on a real modern Android to see yet, as I am using simple mode on my main phone and don't have time to reset the app just now. So any confirmation of what happens for you from Android 11+ beta testers would be appreciated.

(There is also a permissions bug on approx. Android 9 in v2.6.0 but I will fix that likely today.)

[NoelLH]

I fixed the permission bug on Android 9 a few weeks ago I think.

I tested the export behaviour on Android 13 and it did as I expected. So for now I have kept the plugin behaviour as-is but added a clarifying note to the confirmation toast on Android, in 45e6082