按住说话时禁止浏览器默认选择/复制/长按菜单行为

录音期间在 body 上添加 is-voice-recording 类，全局强制
user-select: none、touch-action: none、-webkit-touch-callout: none，
防止按住录音时手指滑动误触浏览器的文字选择和复制功能。

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

frontend/src/views/ChatView.vue

@@ -2256,6 +2256,14 @@ export default {
       }
     })
 
+    watch(isRecording, (recording) => {
+      if (recording) {
+        document.body.classList.add('is-voice-recording')
+      } else {
+        document.body.classList.remove('is-voice-recording')
+      }
+    })
+
     watch([() => currentBackground.value?.id, () => activePetInChat.value?.pet?.id, () => currentPet.value?.id, () => backgroundPets.value.length], async () => {
       syncSelectedHistoryPet()
       historyPage.value = 1
@@ -2310,6 +2318,7 @@ export default {
     }
 
     onUnmounted(() => {
+      document.body.classList.remove('is-voice-recording')
       if (isInCall.value) {
         chatStore.exitCallMode()
         stopCallTimer()
@@ -4360,6 +4369,16 @@ export default {
 
 <!-- 全局样式：teleported到body的单日期选择器 -->
 <style>
+/* 录音期间全局禁止选择和长按菜单，防止按住说话时误触浏览器行为 */
+body.is-voice-recording,
+body.is-voice-recording * {
+  -webkit-user-select: none !important;
+  user-select: none !important;
+  -webkit-touch-callout: none !important;
+  -webkit-tap-highlight-color: transparent;
+  touch-action: none !important;
+}
+
 @media (max-width: 768px) {
   .history-date-single-popper {
     background: rgba(18, 22, 34, 0.95) !important;