feat: Add enableSubagents configuration and wire up subagent registration (#9988)

packages/core/src/agents/invocation.ts

@@ -14,6 +14,7 @@ import type {
   AgentInputs,
   SubagentActivityEvent,
 } from './types.js';
+import type { MessageBus } from '../confirmation-bus/message-bus.js';
 
 const INPUT_PREVIEW_MAX_LENGTH = 50;
 const DESCRIPTION_MAX_LENGTH = 200;
@@ -36,13 +37,15 @@ export class SubagentInvocation extends BaseToolInvocation<
    * @param params The validated input parameters for the agent.
    * @param definition The definition object that configures the agent.
    * @param config The global runtime configuration.
+   * @param messageBus Optional message bus for policy enforcement.
    */
   constructor(
     params: AgentInputs,
     private readonly definition: AgentDefinition,
     private readonly config: Config,
+    messageBus?: MessageBus,
   ) {
-    super(params);
+    super(params, messageBus);
   }
 
   /**