feat(core): migrate chat recording to JSONL streaming (#23749)

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

@@ -141,6 +141,7 @@ vi.mock('../core/geminiChat.js', () => ({
     CHUNK: 'chunk',
   },
   GeminiChat: vi.fn().mockImplementation(() => ({
+    initialize: vi.fn(),
     sendMessageStream: mockSendMessageStream,
     getHistory: vi.fn((_curated?: boolean) => [...mockChatHistory]),
     setHistory: mockSetHistory,
@@ -434,6 +435,7 @@ describe('LocalAgentExecutor', () => {
     MockedGeminiChat.mockImplementation(
       () =>
         ({
+          initialize: vi.fn(),
           sendMessageStream: mockSendMessageStream,
           setSystemInstruction: mockSetSystemInstruction,
           getHistory: vi.fn((_curated?: boolean) => [...mockChatHistory]),

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

@@ -1021,15 +1021,16 @@ export class LocalAgentExecutor<TOutput extends z.ZodTypeAny> {
       : undefined;
 
     try {
-      return new GeminiChat(
+      const chat = new GeminiChat(
         this.executionContext,
         systemInstruction,
         [{ functionDeclarations: tools }],
         startHistory,
         undefined,
         undefined,
-        'subagent',
       );
+      await chat.initialize(undefined, 'subagent');
+      return chat;
     } catch (e: unknown) {
       await reportError(
         e,