feat(idea): create group auto-generates personas; channel removed; product->product/idea

Per product-idea focus:
- GroupBuilder: 'สินค้า/บริการ/ไอเดีย' label; removed the channel select (channel is now
  chosen at chat time as a scenario, not at persona create). Create now auto-runs analyze
  so personas are generated immediately (no separate Analyze button).
- GroupEdit: analyze button becomes 'สร้างบุคคลต้นแบบเพิ่มเติม' which APPENDS more personas
  (backend analyze?append=true reuses sales kit + keeps existing instead of replacing).
- i18n product label updated.
- User-journey test asserts append adds personas (15->30) and existing kept.
All 9 backend suites pass. Rebuilt dist.

frontend/dist/assets/users-DG0hBplh.js

@@ -0,0 +1,6 @@
+import{c as e}from"./index-DNAVmyB5.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 c=e("users",[["path",{d:"M16 21v-2a4 4 0 0 0-4-4H6a4 4 0 0 0-4 4v2",key:"1yyitq"}],["path",{d:"M16 3.128a4 4 0 0 1 0 7.744",key:"16gr8j"}],["path",{d:"M22 21v-2a4 4 0 0 0-3-3.87",key:"kshegd"}],["circle",{cx:"9",cy:"7",r:"4",key:"nufk8"}]]);export{c as U};