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/sparkles-0MI5vUsR.js

@@ -0,0 +1,6 @@
+import{c as a}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 l=a("sparkles",[["path",{d:"M11.017 2.814a1 1 0 0 1 1.966 0l1.051 5.558a2 2 0 0 0 1.594 1.594l5.558 1.051a1 1 0 0 1 0 1.966l-5.558 1.051a2 2 0 0 0-1.594 1.594l-1.051 5.558a1 1 0 0 1-1.966 0l-1.051-5.558a2 2 0 0 0-1.594-1.594l-5.558-1.051a1 1 0 0 1 0-1.966l5.558-1.051a2 2 0 0 0 1.594-1.594z",key:"1s2grr"}],["path",{d:"M20 2v4",key:"1rf3ol"}],["path",{d:"M22 4h-4",key:"gwowj6"}],["circle",{cx:"4",cy:"20",r:"2",key:"6kqj1y"}]]);export{l as S};