feat(app.js, i18n, index.html, styles.css): implement pagination for auth file management

- Added pagination controls to the auth file list in the UI, allowing users to navigate through large sets of files.
- Enhanced the rendering logic to support pagination, including updating the current page and total pages dynamically.
- Updated internationalization strings for pagination in both English and Chinese.
- Introduced new styles for pagination controls to improve user experience and accessibility.

i18n.js

@@ -244,6 +244,9 @@ const i18n = {
             'auth_files.delete_filtered_partial': '{type} 认证文件删除完成，成功 {success} 个，失败 {failed} 个',
             'auth_files.delete_filtered_none': '当前筛选类型 ({type}) 下没有可删除的认证文件',
             'auth_files.files_count': '个文件',
+            'auth_files.pagination_prev': '上一页',
+            'auth_files.pagination_next': '下一页',
+            'auth_files.pagination_info': '第 {current} / {total} 页 · 共 {count} 个文件',
             'auth_files.filter_all': '全部',
             'auth_files.filter_qwen': 'Qwen',
             'auth_files.filter_gemini': 'Gemini',
@@ -737,6 +740,9 @@ const i18n = {
             'auth_files.delete_filtered_partial': '{type} auth files deletion finished: {success} succeeded, {failed} failed',
             'auth_files.delete_filtered_none': 'No deletable auth files under the current filter ({type})',
             'auth_files.files_count': 'files',
+            'auth_files.pagination_prev': 'Previous',
+            'auth_files.pagination_next': 'Next',
+            'auth_files.pagination_info': 'Page {current} / {total} · {count} files',
             'auth_files.filter_all': 'All',
             'auth_files.filter_qwen': 'Qwen',
             'auth_files.filter_gemini': 'Gemini',