fix: correct auth import path in agent-chat route

Was importing from @/lib/auth (which doesn't exist); correct path
is @/lib/auth/authOptions — this caused the Turbopack build to fail.

Made-with: Cursor

app/api/projects/[projectId]/agent-chat/route.ts

@@ -1,6 +1,6 @@
 import { NextRequest, NextResponse } from "next/server";
 import { getServerSession } from "next-auth/next";
-import { authOptions } from "@/lib/auth";
+import { authOptions } from "@/lib/auth/authOptions";
 import { query } from "@/lib/db-postgres";
 
 const AGENT_RUNNER_URL = process.env.AGENT_RUNNER_URL ?? "http://localhost:3333";