Improve chat UX: thinking indicator, pending message, 5min timeout

app/api/sessions/[id]/chat/route.ts

@@ -6,17 +6,23 @@ export async function POST(req: NextRequest, { params }: { params: Promise<{ id:
   const { id } = await params;
   const body = await req.json();
   try {
+    // Agent chat can take a while — 5 minute timeout
+    const controller = new AbortController();
+    const timeout = setTimeout(() => controller.abort(), 300_000);
     const res = await fetch(BACKEND + "/api/sessions/" + id + "/chat", {
       method: "POST",
       headers: { "Content-Type": "application/json" },
       body: JSON.stringify(body),
+      signal: controller.signal,
     });
+    clearTimeout(timeout);
     const data = await res.text();
     return new NextResponse(data, {
       status: res.status,
       headers: { "content-type": "application/json" },
     });
-  } catch {
-    return NextResponse.json({ error: "backend unreachable" }, { status: 502 });
+  } catch (e) {
+    const msg = e instanceof Error ? e.message : "backend unreachable";
+    return NextResponse.json({ error: msg }, { status: 502 });
   }
 }