feat: Translate frontend/src/i18n/en.json in zh_CN

98% of minimum 50% translated source file: 'frontend/src/i18n/en.json'
on 'zh_CN'.

Sync of partially translated files: 
untranslated content is included with an empty translation 
or source language content depending on file format

frontend/src/i18n/zh-cn.json

@@ -82,7 +82,7 @@
     "csvTooLarge": "CSV文件大到无法预览(>5MB)。请下载查看。",
     "csvLoadFailed": "加载 CSV 文件失败。",
     "showingRows": "正在显示 {count} 行",
-    "columnSeparator": "Column Separator",
+    "columnSeparator": "列分隔符",
     "csvSeparators": {
       "comma": "Comma (,)",
       "semicolon": "Semicolon (;)",