修复四个功能按钮互斥：打开历史面板时关闭输入面板

历史面板与文字/语音/通话输入面板重叠导致分页器无法点击。
打开任一功能时自动关闭其他功能，避免 UI 冲突。

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/views/ChatView.vue

@@ -1064,6 +1064,7 @@ export default {
         return
       }
 
+      showHistoryPanel.value = false
       await switchToTextMode()
     }
 
@@ -1714,6 +1715,7 @@ export default {
               return
             }
             await forceStopVoiceAndCall()
+            showHistoryPanel.value = false
             showInputPanel.value = true
             chatMode.value = 'voice'
 
@@ -1878,6 +1880,7 @@ export default {
       }
 
       pendingCallMode = true
+      showHistoryPanel.value = false
       try {
         if (chatStore.isTokenExhausted()) {
           ElMessage.error('Token已耗尽，请充值后再使用')
@@ -2008,6 +2011,9 @@ export default {
     const toggleHistoryPanel = async () => {
       showHistoryPanel.value = !showHistoryPanel.value
       if (showHistoryPanel.value) {
+        if (showInputPanel.value) {
+          await resetToDefaultMode()
+        }
         syncSelectedHistoryPet()
         if (!historyQuickFilter.value) {
           historyQuickFilter.value = 'all'