Set Serverless annotation for ESQL REST endpoint (#103006)

x-pack/plugin/esql/build.gradle

@@ -21,6 +21,7 @@ dependencies {
   implementation project('compute:ann')
   implementation project(':libs:elasticsearch-dissect')
   implementation project(':libs:elasticsearch-grok')
+  // Also contains a dummy processor to allow compilation with unused annotations.
   annotationProcessor project('compute:gen')
 
   testImplementation project('qa:testFixtures')

x-pack/plugin/esql/compute/gen/src/main/java/org/elasticsearch/compute/gen/ConsumeProcessor.java

@@ -39,6 +39,7 @@ public class ConsumeProcessor implements Processor {
             "org.elasticsearch.common.inject.Inject",
             "org.elasticsearch.xpack.esql.expression.function.FunctionInfo",
             "org.elasticsearch.xpack.esql.expression.function.Param",
+            "org.elasticsearch.rest.ServerlessScope",
 
             Fixed.class.getName()
         );

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

@@ -13,6 +13,8 @@ import org.elasticsearch.logging.LogManager;
 import org.elasticsearch.logging.Logger;
 import org.elasticsearch.rest.BaseRestHandler;
 import org.elasticsearch.rest.RestRequest;
+import org.elasticsearch.rest.Scope;
+import org.elasticsearch.rest.ServerlessScope;
 import org.elasticsearch.rest.action.RestCancellableNodeClient;
 import org.elasticsearch.xcontent.XContentParser;
 
@@ -24,6 +26,7 @@ import java.util.Set;
 import static org.elasticsearch.rest.RestRequest.Method.POST;
 import static org.elasticsearch.xpack.esql.formatter.TextFormat.URL_PARAM_DELIMITER;
 
+@ServerlessScope(Scope.PUBLIC)
 public class RestEsqlQueryAction extends BaseRestHandler {
     private static final Logger LOGGER = LogManager.getLogger(RestEsqlQueryAction.class);