feat: enhance persona tool management and update UI localization for subagent orchestration (#4990)

* feat: enhance persona tool management and update UI localization for subagent orchestration

* fix: remove debug logging for final ProviderRequest in build_main_agent function

dashboard/src/i18n/locales/en-US/features/subagent.json

@@ -2,7 +2,7 @@
   "page": {
     "title": "SubAgent Orchestration",
     "beta": "Experimental",
-    "subtitle": "The main LLM only chats and delegates; tools live on individual SubAgents."
+    "subtitle": "The main LLM can use its own tools directly and delegate tasks to SubAgents via handoff."
   },
   "actions": {
     "refresh": "Refresh",

dashboard/src/i18n/locales/zh-CN/features/subagent.json

@@ -2,7 +2,7 @@
   "page": {
     "title": "SubAgent 编排",
     "beta": "实验性",
-    "subtitle": "主 LLM 只负责聊天与分派（handoff），工具挂载在各个 SubAgent 上。"
+    "subtitle": "主 LLM 可直接使用自身工具，也可通过 handoff 分派给各个 SubAgent。"
   },
   "actions": {
     "refresh": "刷新",

dashboard/src/views/SubAgentPage.vue

@@ -142,17 +142,6 @@
                 </v-col>
               </v-row>
 
-              <div class="mt-3">
-                <div class="text-caption text-medium-emphasis">{{ tm('cards.previewTitle') }}</div>
-                <div class="d-flex align-center" style="gap: 8px; flex-wrap: wrap;">
-                  <v-chip size="small" variant="outlined" color="primary">
-                    {{ tm('cards.transferPrefix', { name: agent.name || '...' }) }}
-                  </v-chip>
-                  <v-chip size="small" variant="tonal" color="secondary" v-if="agent.persona_id">
-                    {{ tm('cards.personaChip', { id: agent.persona_id }) }}
-                  </v-chip>
-                </div>
-              </div>
             </v-expansion-panel-text>
           </v-expansion-panel>
         </v-expansion-panels>