fix(scenario): recontact chats normally first then re-engages mid-chat; channel default=social; remove 'add more' button (15 personas auto)

- recontact persona now opens as a NORMAL customer (no 'I asked before' in the opening);
  the mid-chat time-lapse system note (turn 2) makes them re-engage warmer instead.
- channel default changed facebook->social everywhere (create/analyze/store/simulator/me).
- 15 personas auto-generated (TARGET=15); removed the 'สร้างบุคคลต้นแบบเพิ่มเติม' button/guide.
All 9 backend suites pass. Rebuilt dist.

frontend/dist/assets/arrow-left-hWxF5h5m.js

@@ -0,0 +1,6 @@
+import{c as e}from"./index-yErsUbD6.js";/**
+ * @license lucide-vue-next v1.0.0 - ISC
+ *
+ * This source code is licensed under the ISC license.
+ * See the LICENSE file in the root directory of this source tree.
+ */const t=e("arrow-left",[["path",{d:"m12 19-7-7 7-7",key:"1l729n"}],["path",{d:"M19 12H5",key:"x3x0zl"}]]);export{t as A};