Release v15.19.0

What's New

• AI on YouTube: Page AI, Chat with Web, and summarize now work on the video's caption transcript; videos without captions are transcribed with Gemini (when a Gemini API key is configured), and transcripts are cached so each video is only transcribed once
• Userscripts can be exported/imported as a zip compatible with other userscript managers, and are now included in app-data backup and Google Drive sync
• AI chat sessions are stored in the app database, survive WebView storage clearing, and are included in backup/restore and Drive sync together with video transcripts; backup and restore dialogs show per-category sizes
• Web pages with their own read-aloud buttons now speak through the app's TTS engine (system, Edge-TTS, or OpenAI) via a Web Speech API polyfill
• Paragraph translations are cached for 7 days, so revisited pages translate instantly
• Bookmarks grid: long press shows the context menu and lets the finger slide onto an action, triggering it on lift (with "1 touch to url action" enabled)

Bug Fixes

• Reader mode no longer blanks the page after following a link from a reader-mode page (#309)
• Site stylesheets are disabled while reader mode is showing, fixing collapsed layouts on some sites
• Settings rows and menu cells grow with larger system font sizes instead of clipping text (#623)
• Pages no longer freeze with unloaded content after returning to the app
• About screen no longer shows a stale build timestamp