feat: support advertised tempo charge modes

[brendanjryan]

Summary

• add supportedModes to the Tempo charge request schema and serialize it into methodDetails
• negotiate client submission mode from the server-advertised modes, while preserving the existing default preference order
• reject hash or transaction credentials on the server when the challenge did not advertise the corresponding mode
• add regression coverage for schema serialization, client-side rejection, server-side rejection, and emitted challenges
• add a patch changeset for the Tempo charge supported-modes behavior

Context

This matches the Tempo charge spec update in tempoxyz/mpp-specs#243, where: