Add bech32m PR encoding for unified QR codes

[Egge21M]

Description

This adds the new bech32m and TLV based Payment Request encoding (creqB). We use @scure/base for bech32m and bech32 encoding. This dependency was transiently installed through @scure/bip32 already, so this should not affect our dep graph.

Changes

• Adds tlv.ts with TLV encoding utils for Payment Requests and nostr nprofiles (required for noramlization)
• Adds bech32m.ts that wraps @scure/base utils for convenience and isolation
• Adds two new methods to PaymentRequest
  1. toEncodedCreqA (delegates to toEncodedRequest for compatibility
  2. toEncodedCrewB (new API)

PR Tasks

• Open PR
• run npm run test --> no failing unit tests
• run npm run lint --> no warnings or errors
• run npm run format
• run npm run api:check --> run npm run api:update for changes to the API

[robwoodgate]

LGTM! Hats off to you, this is a seriously impressive bit of code, and I love that you've included all the test vectors from the NUT.

My only question (which @thesimplekid may want to input on) is what about the P2BK flag to signal that the PR should use blinded keys. Currently we have that implemented as a nut26 boolean, at same level as the nut10 tag, but it is not represented here.

[TheRealCheebs]

Looks good and clean.

[Egge21M]

@robwoodgate should we merge this and simply add P2BK once the NUT has been adjusted? I think P2BK signaling is not part of the spec right now and shouldn't block this.

[robwoodgate]

@robwoodgate should we merge this and simply add P2BK once the NUT has been adjusted? I think P2BK signaling is not part of the spec right now and shouldn't block this.

Yes, let's not let P2BK hold it up. I have removed all NUT-18 from P2BK pending another review, so this is correct to current spec.