Version 3 is here for Firefox! 🎉

This release brings Firefox up to date with all the improvements from the
Chrome version:
- More reliable detection that survives DeepSeek UI changes
- Light Mode + Dark Mode support
- "Always Hide" setting to hide thoughts automatically
- Manual control, open any thought and it stays open
- Better handling when switching between chats

Thanks for your patience while Firefox support was unavailable, and please
report any issues!

Fixed bug: Manually toggled thoughts no longer auto-close.