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/lock-BhsUQe9Y.js

@@ -0,0 +1,6 @@
+import{c as e}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 t=e("lock",[["rect",{width:"18",height:"11",x:"3",y:"11",rx:"2",ry:"2",key:"1w4ew1"}],["path",{d:"M7 11V7a5 5 0 0 1 10 0v4",key:"fwvmzm"}]]);export{t as L};