feat: add custom parameter support to /ytdlp command (#185), close #184

* Initial plan

* Implement parameter support for /ytdlp command

Co-authored-by: krau <71133316+krau@users.noreply.github.com>

* Add comprehensive tests for ytdlp parameter parsing

Co-authored-by: krau <71133316+krau@users.noreply.github.com>

* Improve flag parsing logic and clarify argument order

Co-authored-by: krau <71133316+krau@users.noreply.github.com>

* Preserve critical defaults and improve comments

Co-authored-by: krau <71133316+krau@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: krau <71133316+krau@users.noreply.github.com>

common/i18n/locale/en.yaml

@@ -289,7 +289,7 @@ bot:
       error_no_valid_links: "No valid links to download"
       info_files_select_storage: "Total {{.Count}} files, please select storage"
     ytdlp:
-      usage: "Usage: /ytdlp <URL1> <URL2> ..."
+      usage: "Usage: /ytdlp [OPTIONS] <URL1> [URL2] ...\nExamples:\n  /ytdlp https://example.com/video\n  /ytdlp --format best https://example.com/video\n  /ytdlp --extract-audio --audio-format mp3 https://example.com/video"
       error_no_valid_urls: "No valid URLs"
       info_urls_select_storage: "Found {{.Count}} links, please select storage"
       info_downloading: "Downloading via yt-dlp..."

common/i18n/locale/zh-Hans.yaml

@@ -290,7 +290,7 @@ bot:
       error_no_valid_links: "没有有效的链接可供下载"
       info_files_select_storage: "共 {{.Count}} 个文件, 请选择存储位置"
     ytdlp:
-      usage: "用法: /ytdlp <URL1> <URL2> ..."
+      usage: "用法: /ytdlp [选项] <URL1> [URL2] ...\n示例:\n  /ytdlp https://example.com/video\n  /ytdlp --format best https://example.com/video\n  /ytdlp --extract-audio --audio-format mp3 https://example.com/video"
       error_no_valid_urls: "没有有效的 URL"
       info_urls_select_storage: "共 {{.Count}} 个链接, 请选择存储位置"
       info_downloading: "正在通过 yt-dlp 下载..."

common/utils/ioutil/writer.go

@@ -48,4 +48,4 @@ func NewProgressWriter(
 		wr:      wr,
 		onWrite: onWrite,
 	}
-}
+}