Files · Explorer: a folder as a list, tiles or columns, with one path and one order

FileExplorer shows the folder at the end of a path three ways: the
directory listing, a grid of tiles, or a column per folder along the
path with the next folder lit. Its name, its count and a switch of views
sit above one path bar that climbs. A folder opens in place; a file goes
to the host, which lists each folder it goes to. A pick in an earlier
column closes the columns past it, and a new deepest column scrolls into
view. The directory listing takes its pick from its owner and reports
it, so the pick carries across views; its path bar and its first order
are shared. The gallery walks a small file system and shows the tree,
the context menu, renaming in place and a drop zone in use.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

AGENTS.md

@@ -113,6 +113,7 @@ Ely GPUI Component. A component library for GPUI, in light and dark.
 - gpui 0.2.2's `line_clamp` wraps once and lays the rest on the last line, cut hard; centered, it loses both ends. A name whose ends matter is a `typography::MiddleEllipsis` on one line (`files::FileGrid`).
 - Set an explicit line height on any box that clips text. gpui's default leading is taller than a tight box, and the clip eats descenders.
 - gpui's `img` takes its picture's pixel size for any `Auto` side, and its aspect ratio beats percent heights in flow. `Image` pins it absolute at full size, so an `Image` needs a sized box.
+- A folder's path over its entries is `lists::path_bar`, and its first order is `lists::listed`, folders first by name: DirectoryListing and FileExplorer share both, so every view shows one path and one order.
 - A file's icon comes from `primitives::file_icon`, one map from name to icon for every chapter; `files::FileIcon` draws it. What fits across a width comes from `layout::columns_for`, and `layout::fit` adds the inset that centers it.
 - Badges, tags and avatars live in `data_display`; forms and shell draw theirs from there, and `data_display` imports neither. Avatars take square pictures.
 - A picture drawn in code reaches gpui as a `RenderImage`. A host that replaces one frees the old through `App::drop_image`, or every frame stays in the sprite atlas (the gallery's model).