's'

app/api/join/route.ts

@@ -101,7 +101,7 @@ export async function POST(request: NextRequest) {
       return NextResponse.json({ ok: false, error: errMsg }, { status: 500 });
     }
 
-    return NextResponse.json({ ok: true });
+    return NextResponse.json({ ok: true, user_id: userId });
   } catch (e) {
     const msg = e instanceof Error ? e.message : String(e);
     console.error("Join API error:", e);