fix: 修复对话视图合并后的问题

- 移除未使用的变量 index
- 修复展开/收缩按钮在非请求体Tab被禁用的问题
- 删除未使用的 copyJsonToClipboard 函数

Co-Authored-By: LewisPen <LewisPen@nyadoo.com>

frontend/src/features/usage/components/RequestDetailDrawer.vue

@@ -393,10 +393,10 @@
                         <button
                           :title="currentExpandDepth === 0 ? '展开全部' : '收缩全部'"
                           class="p-1.5 rounded transition-colors"
-                          :class="viewMode === 'compare' || contentViewMode === 'conversation'
+                          :class="viewMode === 'compare' || (supportsConversationView && contentViewMode === 'conversation')
                             ? 'text-muted-foreground/40 cursor-not-allowed'
                             : 'text-muted-foreground hover:bg-muted'"
-                          :disabled="viewMode === 'compare' || contentViewMode === 'conversation'"
+                          :disabled="viewMode === 'compare' || (supportsConversationView && contentViewMode === 'conversation')"
                           @click="currentExpandDepth === 0 ? expandAll() : collapseAll()"
                         >
                           <Maximize2
@@ -880,42 +880,6 @@ function getTierRangeText(tier: { up_to?: number | null }, index: number, tiers:
   return `> ${formatNumber(start)} tokens`
 }
 
-function copyJsonToClipboard(tabName: string) {
-  if (!detail.value) return
-  // 对比模式下不允许复制
-  if (viewMode.value === 'compare') return
-
-  let data: any = null
-  switch (tabName) {
-    case 'request-headers':
-      // 根据当前数据源选择要复制的数据
-      data = dataSource.value === 'provider'
-        ? detail.value.provider_request_headers
-        : detail.value.request_headers
-      break
-    case 'request-body':
-      data = detail.value.request_body
-      break
-    case 'response-headers':
-      data = actualResponseHeaders.value
-      break
-    case 'response-body':
-      data = detail.value.response_body
-      break
-    case 'metadata':
-      data = detail.value.metadata
-      break
-  }
-
-  if (data) {
-    copyToClipboard(JSON.stringify(data, null, 2), false)
-    copiedStates.value[tabName] = true
-    setTimeout(() => {
-      copiedStates.value[tabName] = false
-    }, 2000)
-  }
-}
-
 // 复制内容（支持 JSON 和对话两种模式）
 function copyContent(tabName: string) {
   if (!detail.value) return

frontend/src/features/usage/utils/messageExtractor.ts

@@ -278,7 +278,7 @@ function extractClaudeStreamResponse(chunks: any[]): ExtractedConversation {
   }
 
   // 转换为消息
-  for (const [index, block] of Array.from(blocks.entries()).sort((a, b) => a[0] - b[0])) {
+  for (const [, block] of Array.from(blocks.entries()).sort((a, b) => a[0] - b[0])) {
     result.messages.push({
       role: 'assistant',
       content: block.parts.join(''),