ResourceServerExtension registrations for all CDP-supported extensions.
These register enrichment handlers on x402ResourceServer so that routes
whose extensions include a CDP extension key get the correct
PaymentRequired.extensions[key] value.
createX402Server() calls this automatically. Call it manually only when
building a resource server without createX402Server:
Returns
ResourceServerExtension[]
Array of ResourceServerExtension registrations for gas-sponsoring and Bazaar.