Elements
The six elements the runtime renders, plus slot, router and route.
<screen> <view> <text> <image> <path> <button> <input> + imported
components as custom tags, plus two that render no box of their own: <slot>
(a component's hole for the caller's children) and <router>/<route> (see
Routing). role= is honored for selectors and semantics
(and matches case-insensitively: role="Heading" matches [role="heading"]).
<image src="assets/logo.png">: src resolves relative to the .rux file
(not the working directory), and :src binds an expression. With no CSS size it
lays out at the file's intrinsic pixel size; a width/height scales it to fit.
Formats: PNG, JPEG, GIF, WebP. A missing file logs to stderr and paints nothing.