UI.20 Theme switch: sun and moon icons for light and dark wherever the interface says "Paper" and "Model"

Owner 2026-11-09: where we say "paper/model" we switch to sun/moon icons for the light and dark themes. Today the theme toggle is a two-button form with the words Paper and Model: the site navbar (navbar.inc, titles "Paper space: light theme" / "Model space: dark theme"), the app bar in every app and its More menu on phones (app-bar.inc, words shell.bar.paper / shell.bar.model and their titles), the Settings radios (app-settings.inc already draws bi-sun next to "Paper"; shell.settings.theme.paper / .model), and the pre-paint script and site.js that read them. Change: one shared toggle component (space-toggle.inc) drawn as two icon buttons, a sun for light and a moon for dark, from the CadCraft icon set (UI.14: two new drawings, sun and moon, in all three styles) with the pressed state lit, aria-labels and tooltips "Light theme" / "Dark theme" (plus "Match the system" where Settings offers it), the words shell.bar.light / shell.bar.dark in en, es-MX and id and the old keys retired by bin/test-shell-lang.mjs; the navbar, the app bar, its More menu, Settings and the Studio hub use the one component. What stays: the stored values paper / model (localStorage cc-space, the cc_space cookie, data-space) and the brand file names cadcraft-logo-{paper,model}: internal names, nothing a person reads, so no stored setting breaks. What this does NOT touch: CadCraft's real paper space and model space (the drawing's layouts and the MODEL / PAPER status toggle), which keep their names because that is what they are. Help: the theme line in common/getting-started topics; the FAQ answer that names Paper and Model, if any, re-read. Owner addition the same day: in the apps the sun and moon are one row of two icon buttons inside the Craft menu, which opens from the app mark and name at the far left of the absolute top (UI.8, UI.24); icons in a row, never list items; the website navbar keeps its own pair.