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.

backend/app/api/me_routes.py

@@ -74,7 +74,7 @@ def _personal_group(s, actor) -> dict:
         g["id"],
         status="ready",
         owner_user_id=actor["id"],
-        input={"channel": "facebook", "language": "th"},
+        input={"channel": "social", "language": "th"},
         sales_kit={"productName": "personal practice", "valueProps": [], "features": []},
     )
     return s["groups"].get(g["id"])