refactor(scenario): only 2 scenarios (social / face-to-face); 're-contact' becomes a persona trait

- Scenario picker now has only social + f2f_call (removed recontact) in backend
  _scenarios, start_session validation, and Chat.vue picker.
- 'ลูกค้ากลับมาติดต่อ' is no longer a scenario: it's now a PERSONA trait. Persona prompt
  generates ~1-in-4 personas with recontact=true (asked before, now returns warmer/ready);
  store shape gets recontact field; simulator injects a re-contact note into the persona's
  system prompt so it plays as a returning customer naturally.
- test_scenario updated: unknown scenario defaults to social; recontact shown as a
  generated persona trait.
All 9 backend suites pass. Rebuilt dist.

frontend/dist/assets/layout-dashboard-DNjo1OkM.js

@@ -0,0 +1,6 @@
+import{c as t}from"./index-rfeHzF-F.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 h=t("layout-dashboard",[["rect",{width:"7",height:"9",x:"3",y:"3",rx:"1",key:"10lvy0"}],["rect",{width:"7",height:"5",x:"14",y:"3",rx:"1",key:"16une8"}],["rect",{width:"7",height:"9",x:"14",y:"12",rx:"1",key:"1hutg5"}],["rect",{width:"7",height:"5",x:"3",y:"16",rx:"1",key:"ldoo1y"}]]);export{h as L};