server/src/routes/chat.ts

```typescript
import { Router } from "express";
import { z } from "zod";
import { rosalindaRespond } from "../core/agent.js";

export const chatRouter = Router();

chatRouter.post("/", async (req, res) => {
  const body = z.object({
    projectId: z.string().min(1),
    text: z.string().min(1)
  }).safeParse(req.body);

  if (!body.success) return res.status(400).json({ ok: false, error: body.error.message });

  const out = await rosalindaRespond({ projectId: body.data.projectId, userText: body.data.text });
  res.json({ ok: true, reply: out.reply, toolResult: out.toolResult });
});
```