feat: add CAMELEER_OIDC_JWK_SET_URI for direct JWKS fetching

When set, fetches JWKs from this URL directly instead of discovering
from the OIDC well-known endpoint. Needed when the public issuer URL
(e.g., https://domain.com/oidc) isn't reachable from inside containers
but the internal URL (http://logto:3001/oidc/jwks) is.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cameleer3-server-app/src/main/resources/application.yml

@@ -51,6 +51,7 @@ security:
   ui-origin: ${CAMELEER_UI_ORIGIN:http://localhost:5173}
   jwt-secret: ${CAMELEER_JWT_SECRET:}
   oidc-issuer-uri: ${CAMELEER_OIDC_ISSUER_URI:}
+  oidc-jwk-set-uri: ${CAMELEER_OIDC_JWK_SET_URI:}
   oidc-audience: ${CAMELEER_OIDC_AUDIENCE:}