i18n(ui): clarify preview build and extended image-recognition copy

Notes the preview build as unofficial in the conversation hero and describes the
image-recognition plugin as an extension beyond the official DeepSeek surface.

Co-Authored-By: Claude <noreply@anthropic.com>

packages/client/ui-conversation/src/client/locales.ts

@@ -71,7 +71,7 @@ export const zh = {
   'access.confirm.cancel': '取消',
   'access.confirm.enable': '启用 Full access',
   'hero.headline': '探索未至之境',
-  'hero.preview': '预览版',
+  'hero.preview': '预览版 · 非官方',
   'hero.chooseWorkspace': '选择工作区',
   'session.hierarchy': '会话层级',
   'details.title': '详情',
@@ -240,7 +240,7 @@ export const en = {
   'access.confirm.cancel': 'Cancel',
   'access.confirm.enable': 'Enable Full access',
   'hero.headline': 'Into the Unknown',
-  'hero.preview': 'Preview',
+  'hero.preview': 'Preview · Unofficial',
   'hero.chooseWorkspace': 'Choose workspace',
   'session.hierarchy': 'Session hierarchy',
   'details.title': 'Details',