Add passkey owner and delegated account-client auth

[seichris]

Summary

• add passkey-owner and delegated-access-key authorization support to the SDK
• add the FastAccountClient prepared-transaction authorization flow
• align passkey and delegated envelope shapes with the protocol model

Verification

• npm run build
• npm test

[seichris]

Related PRs in the cross-repo passkey/delegated-access-key work:

• Fast protocol: https://github.com/fastxyz/Fast/pull/1200
• fast-connector: https://github.com/fastxyz/fast-connector/pull/7
• app.fast.xyz: https://github.com/fastxyz/app.fast.xyz/pull/1

Related repos:

• fast-embedded-wallet: https://github.com/fastxyz/fast-embedded-wallet
• fast-key-manager: https://github.com/fastxyz/fast-key-manager