Replace flow-service proxy for user-onramp with direct Coinbase + Openfort
provider calls. Eliminates double-hop dependency and simplifies deployment.
- Add CoinbaseOnrampProvider (Ed25519 JWT → CDP session → widget URL)
- Add OpenfortProvider (smart wallet creation on Base)
- Initialize providers from env vars in onInit()
- Update folk-flows-app to support Coinbase widget alongside Transak
- Add jose and @openfort/openfort-node dependencies
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
