feat(core,cli): enforce mandatory MessageBus injection (Phase 3 Hard Migration) (#15776)

packages/core/src/agents/local-invocation.ts

@@ -37,13 +37,13 @@ export class LocalSubagentInvocation extends BaseToolInvocation<
    * @param definition The definition object that configures the agent.
    * @param config The global runtime configuration.
    * @param params The validated input parameters for the agent.
-   * @param messageBus Optional message bus for policy enforcement.
+   * @param messageBus Message bus for policy enforcement.
    */
   constructor(
     private readonly definition: LocalAgentDefinition,
     private readonly config: Config,
     params: AgentInputs,
-    messageBus?: MessageBus,
+    messageBus: MessageBus,
     _toolName?: string,
     _toolDisplayName?: string,
   ) {