feat: 新增群员统计与退群事件，并把本地索引集中到设置页

- 群员统计：档案中按群统计发言排行与未发言成员，可复制纯文本、按平台能力发送
- 退群事件永久保存，并以本地推断条目并入档案消息流
- 设置新增本地索引页，集中管理聊天记录索引与图片文字索引

tests/component/chat-header-group-stats.test.tsx

@@ -0,0 +1,65 @@
+import { render, screen, waitFor } from '@testing-library/react'
+import userEvent from '@testing-library/user-event'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { ChatHeader } from '../../src/renderer/src/components/chat/ChatHeader'
+import { TooltipProvider } from '../../src/renderer/src/components/ui'
+import type { Contact } from '../../src/shared/types'
+
+const groupContact: Contact = {
+  m_nsUsrName: '研发群@chatroom',
+  m_nsNickName: '研发群',
+  md5: 'g'.repeat(32),
+  type: 'group'
+}
+
+const userContact: Contact = {
+  m_nsUsrName: 'wxid_friend',
+  m_nsNickName: '好友',
+  md5: 'u'.repeat(32),
+  type: 'user'
+}
+
+beforeEach(() => {
+  ;(window as unknown as { api: Record<string, unknown> }).api = {
+    getGroupMemberStats: vi.fn(),
+    getPersonalWechatSenderStatus: vi.fn().mockResolvedValue({ canSendText: false })
+  }
+})
+
+function renderHeader(contact: Contact, isGroupChat: boolean): void {
+  render(
+    <TooltipProvider>
+      <ChatHeader
+        contact={contact}
+        isGroupChat={isGroupChat}
+        loadedCount={10}
+        filteredCount={10}
+        contentFilter=""
+        isAiLoading={false}
+        onContentFilterChange={vi.fn()}
+        onTestSend={vi.fn()}
+        onOpenAiSettings={vi.fn()}
+      />
+    </TooltipProvider>
+  )
+}
+
+async function openMoreMenu(): Promise<void> {
+  const user = userEvent.setup()
+  await user.click(screen.getByRole('button', { name: '更多功能' }))
+  await waitFor(() => expect(screen.getByText('刷新数据')).toBeTruthy())
+}
+
+describe('ChatHeader · 群发言统计入口', () => {
+  it('群聊显示「群发言统计」入口', async () => {
+    renderHeader(groupContact, true)
+    await openMoreMenu()
+    expect(screen.getByText('群发言统计')).toBeTruthy()
+  })
+
+  it('非群聊不显示「群发言统计」入口', async () => {
+    renderHeader(userContact, false)
+    await openMoreMenu()
+    expect(screen.queryByText('群发言统计')).toBeNull()
+  })
+})