support react-native

[getify]

support via https://www.npmjs.com/package/react-native-passkeys which mimics the WebAuthn navigator.credentials API.

also need to get the following working in react-native:

• CBOR
• ASN1
• libsodium

[getify]

this library also relies on crypto.subtle for its SHA256 hash, as well as for verification of non-Ed25519 signatures (since sodium only supports Ed25519 signatures). but react-native doesn't have crypto.subtle... so need to figure out some replacement for these pieces.

[getify]

possible solution to the crypto.subtle issue: https://github.com/webview-crypto/react-native-webview-crypto

[getify]

also need to patch over missing PublicKeyCredential:

• PublicKeyCredential.isUserVerifyingPlatformAuthenticatorAvailable()
• PublicKeyCredential.isConditionalMediationAvailable()

[getify]

also need to adapt to the fact that the react-native-passkeys API (create(), get()) doesn't actually match the WebAuthn API exactly, specifically that in WebAuthn, you call create({ publicKey: { ... } }) but in the RN library, you call just create({ ... }).

[getify]

Have decided against this approach.