fix: preserve source data and recover tool math at presentation

src/core/index.ts

@@ -47,6 +47,7 @@ export * from "./input-events.ts";
 // the deleted server projection to the client side. Pure, browser-safe.
 export * from "./view.ts";
 export * from "./tool-parts.ts";
+export * from "./answer-presentation.ts";
 export * from "./prices.ts";
 export * from "./context-usage.ts";
 export type { ChatGPTStatus, ChatGPTControlBridge } from "./contracts/chatgpt.ts";