Kit · K03: init checks every bundled file through the app's source; Assets::before joins another source

AGENTS.md

@@ -149,6 +149,7 @@ Ely GPUI Component. A component library for GPUI, in light and dark.
 - Pixels a host draws at a box's size go through `rendering::RenderSurface`: it asks for one BGRA frame at the box's device pixels in prepaint, draws again only for a new size or revision, and frees the old frame and, on leave, the last one. The revision covers all the frame reads, theme colors too.
 - Tests type a shortcut as it is bound: a `secondary-` binding is Command on macOS and Control elsewhere, so its test types `secondary-`; `cmd-` is the platform key on every OS and reaches only handlers that read that modifier (`lists::SelectableList`). A Tab count runs through `forms::EyeDropper` only on macOS, where it is enabled.
 - `img()` keeps loading state, and moves an animated picture's frames, only with an id; the frames hold still while its window is inactive or gpui's own `reduce_motion` is on, which the theme's reduced motion does not set. Content masks are rectangles, but `img()` draws only the part of its picture inside its box and rounds that part with its own radius, so a `Cover` crop keeps its corners.
+- An app has one asset source: `Assets`, or `Assets::before(other)` when it has files of its own or runs another library such as GPUI Kit; Ely's paths load from Ely, the rest from `other`. `init` loads every file Ely bundles through the app's source and fails naming the first it cannot, since gpui's svg renderer reads IBM Plex there too.
 - gpui reads a `&str` picture source with a scheme as a web address, and any other as an embedded asset. A file goes through `Path` (`documents::source` in the crate, `ui::picture` in the gallery).
 - Taffy sizes a flex column by the height a ratio box has at its set width, before its cap, so chat's `shaped` pictures sit in a block inside such a column (`chat::ImageMessage`, `VideoMessage`, `ImageGrid`).
 - Taffy 0.13 collapses a child's vertical margin through a block parent with no padding or border on that side, and its size cache keeps only that block's size, so a box that measures it again leaves the margin out. A component moves a box with a relative offset, or with padding where what follows moves too, not with such a margin: `layout::Drawer` pulls and snaps its panel, and a fullscreen `overlays::Dialog` slides its card, with `top`; `motion::Stagger`, `Transition`, a centered Dialog and the palette's card rise with padding, so the box a scrim centers grows with them; the gallery's inspector sample is its probe's own child. A margin that stops at its parent is safe: a flex or grid item's own, or a child's of a flex item or of a box with padding or a border on that side. A flex wrapper stops the collapse but gives its items a definite height, so percent heights inside start to resolve (the Drawer's `max_h(relative(0.85))`).