Add and update strings for download and errors

Expanded and updated translation files (ja, pt, ru, tr, zh) with new keys for download progress, error messages, playlist info, and subtitle selection. This improves localization coverage and user feedback during download and error scenarios.

languages/zh.json

@@ -153,6 +153,22 @@
   },
   "download": {
     "preparing": "正在准备下载...",
+    "starting": "🚀 正在开始下载...",
+    "fetching_info": "🔍 正在获取视频信息...",
+    "preparing_streams": "🎯 正在准备视频流...",
+    "downloading_audio": "⏬ 正在下载音频...",
+    "downloading_video": "⏬ 正在下载视频...",
+    "downloading_subtitle": "⏬ 正在下载字幕...",
+    "downloading": "⏬ 正在下载...",
+    "completed": "✅ 下载完成!",
+    "video_completed": "✅ 视频下载完成!",
+    "audio_completed": "✅ 音频下载完成!",
+    "subtitle_completed": "✅ 字幕下载完成!",
+    "completed_cleaning": "✅ 下载完成!正在清理...",
+    "cancelled": "下载已取消",
+    "processing_playlist": "📋 正在处理播放列表数据...",
+    "paused": "下载已暂停",
+    "resumed": "下载已恢复",
     "please_enter_url": "请先输入网址。",
     "please_set_path": "请先设置下载路径。",
     "please_enter_url_and_path": "请输入网址并设置下载路径。",
@@ -187,7 +203,8 @@
     "updating_from_to": "⬆️ 从 {current} 更新到 {latest}...",
     "running_pip_install": "📦 运行 pip install --upgrade...",
     "pip_completed": "✅ pip 更新完成成功！",
-    "pip_failed": "❌ pip 更新失败：{error}"
+    "pip_failed": "❌ pip 更新失败：{error}",
+    "already_up_to_date": "✅ yt-dlp已是最新版本！"
   },
   "about": {
     "title": "关于 YTSage",
@@ -328,6 +345,34 @@
   "status": {
     "ready": "准备就绪",
     "file_exists": "⚠️ 文件已存在",
+    "video_file_exists": "⚠️ 视频文件已存在",
+    "audio_file_exists": "⚠️ 音频文件已存在",
+    "subtitle_file_exists": "⚠️ 字幕文件已存在",
     "cancelling": "正在取消下载..."
+  },
+  "errors": {
+    "playlist_no_videos": "错误：播放列表不包含有效视频。",
+    "playlist_no_url": "错误：无法获取播放列表第一个视频的URL。",
+    "ytdlp_not_found": "错误：未找到yt-dlp可执行文件。请先安装yt-dlp。",
+    "ytdlp_not_found_path": "错误：未找到yt-dlp可执行文件。这可能是由于安装不当或PATH问题。",
+    "no_data_returned": "错误：yt-dlp未返回数据",
+    "no_format_info": "错误：无可用格式信息。",
+    "analysis_timeout": "错误：分析超时。请重试。",
+    "invalid_speed_limit": "❌ 错误：设置中设置了无效的速度限制值。",
+    "ytdlp_failed": "错误：yt-dlp失败：{error}",
+    "parse_failed": "错误：解析yt-dlp输出失败：{error}",
+    "analysis_failed": "错误：分析失败：{error}",
+    "generic_error": "错误：{error}"
+  },
+  "update_dialog": {
+    "title": "有可用更新"
+  },
+  "playlist": {
+    "unknown": "未知播放列表",
+    "total_videos": "总视频数：{count}",
+    "display_format": "播放列表：{title} | {count}个视频"
+  },
+  "subtitle_selection": {
+    "count_selected": "已选择{count}个"
   }
 }