Headless admin facade for spring-setting: list, get, patch (JSON Merge Patch), replace, and clear-all operations over registered Setting types, with a pluggable authorization SPI.

Spring WebFlux REST + Spring Security adapter for spring-setting-admin: exposes the admin operations over HTTP with per-type per-operation role-based ACL and three pluggable auth modes (Keycloak JWT, HTTP Basic, NOOP for tests).