Add INFERENCE_CCQ_SUPPORT capability

Author: afoucret

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/action/EsqlCapabilities.java

@@ -1683,6 +1683,11 @@ public enum Cap {
          * KNN function adds support for k and visit_percentage options
          */
         KNN_FUNCTION_OPTIONS_K_VISIT_PERCENTAGE,
+
+        /**
+         * Support for inference in cross-cluster queries (CCQ)
+         */
+        INFERENCE_CCQ_SUPPORT,
         // Last capability should still have a comma for fewer merge conflicts when adding new ones :)
         // This comment prevents the semicolon from being on the previous capability when Spotless formats the file.
         ;