feat(core): Thread AgentLoopContext through core. (#21944)

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

@@ -67,6 +67,11 @@ describe('LocalSubagentInvocation', () => {
   beforeEach(() => {
     vi.clearAllMocks();
     mockConfig = makeFakeConfig();
+    // .config is already set correctly by the getter on the instance.
+    Object.defineProperty(mockConfig, 'promptId', {
+      get: () => 'test-prompt-id',
+      configurable: true,
+    });
     mockMessageBus = createMockMessageBus();
 
     mockExecutorInstance = {