Turn YouTube and X video subtitles into a learning surface.
Click any word in the original subtitle: the video pauses and an AI card explains the word in the context of the current sentence and its translation. The card runs your chosen custom AI action (Dictionary by default), so you can save the word to your Notebase, regenerate, or switch providers right there.
Drag across several words: they highlight one by one, and the selection toolbar pops up with translate, read-aloud and your custom AI actions, the same way it works on web pages.
Works for languages without spaces too, such as Chinese and Japanese, with word-level segmentation.
Pick which AI action word lookup uses in Settings → Video Subtitles.
Later: the same word lookup in the sidebar transcript, and highlighting words you've already saved when they show up again.
让 YouTube 和 X 的视频字幕变成学习入口。
单击原文字幕里的任意单词：视频暂停，弹出 AI 卡片，结合当前句和译文解释这个词。卡片跑的是你配置的自定义 AI 指令（默认词典），可以直接保存到生词本、重新生成或切换模型。
按住拖选多个词：逐词高亮，松手后弹出划词工具栏，翻译、朗读、自定义 AI 指令都在，和网页上的划词体验一致。
支持中文、日文等没有空格的语言，按词切分。
在 设置 → 视频字幕 里选择点词学习使用哪个 AI 指令。
后续：侧边栏字幕列表里同样可以点词；已收藏的词再次出现时高亮提示。
