@ now mentions folders and files at any depth
Type @ to point the agent at a folder or a file. Folders open as you pick them, so you can walk down to the exact file you mean.
Point at anything in your project
The @ list used to show only files at the top of your project. It now shows folders too, marked with a slash, and picking one lists what is inside so you can keep going.
Type part of a name after a folder, like @src/comp, to narrow that folder. Picking a file finishes the mention and you keep typing.