bf5adadb24
6 routes over Payment, composite key (customernumber + checknumber), proxying to classic-models-api. openid-connect with RFC 8693 token exchange to classic-models-api audience, rate-limiting, proxy-cache, audit-log — same structure as customers-api's REST layer. Keycloak (local): payments-api-audience client scope + payments-api resource client added, attached to kong-token-exchange-broker's default scopes. No dedicated protocol mappers on payments-api itself, same practice as customers-api/mcp-customers. No MCP layer — same as customers-api, not needed yet.