fix: enhance user agent detection to support custom user agent

CHANGELOG_CN.md

@@ -6,6 +6,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ## [Unreleased]
 
+- 为所有包添加 `ESM` 版本如 `artplayer/dist/artplayer.esm.js`
+- 识别 `globalThis.CUSTOM_USER_AGENT` 全局变量，用于自定义 `navigator.userAgent`
+
 ## [5.2.3] - 2025-04-20
 
 - 添加越南语 `vi`