Paste from clipboard into QR scan screen

[chuck-h]

Is your feature request related to a problem? Please describe.
Sometimes it is awkward to get a transaction from another application into LW in order to use LW as a signing wallet.
This new feature would make LW more flexible and easier to interoperate in a larger ecosystem.

Describe the solution you'd like
Add a "paste" icon to the QR scan screen, similar to Anchor:

Depending on the contents of the clipboard:

1. If the clipboard contains a QR image, process it as if captured by camera
2. If the clipboard contains ESR text, process it

This is a basic functionality. The paste processor could become pretty "smart" as far as recognizing other requested actions from the clipboard (e.g. an invite code).

[chuck-h]

Still a "nice to have" IMHO but not particularly high priority.

I often use Light Wallet as a transaction signer along with a laptop/desktop running a browser. A browser app (e.g. a marketplace, Rainbow token manager, Hypha DAO) presents a QR code on screen and I scan it with my phone. This doesn't work smoothly without the laptop (i.e using a browser running on the phone), but this enhancement would help alot.

I looked at this again today. The standard Flutter Clipboard service cannot paste images (text/plain only), but this package will: https://pub.dev/packages/super_clipboard . Meanwhile mobile_scanner has an analyzeImage interface which will run the barcode processing on an image from a file. So we could copy the clipboard image into a local temporary file, then call the barcode analyzer.

FWIW mobile_scanner keeps making breaking changes but we should probably look at keeping up with the upgrades.