Let menu entries appear as buttons with icon, colours and phone placement

The menu editor gets "Als Button darstellen" per entry: shape, appearance and
size from the button design, fill and ink with hover and palette, icon colour,
icon from the dialog, motion, icon-only and where the button sits on the phone
(in the opened menu, beside the burger, or there as an icon only). Colours go
into the page stylesheet under a stable per-button id because the CSP forbids
inline styles. ADR 110.

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

src/Controller/EditorController.php

@@ -492,7 +492,7 @@ final class EditorController extends AbstractController
                 // CSS, Bereichs- und Sektionsstilen und der Formulare mit ihren Farben. Vorher
                 // fehlte all das, und "sieht in der Vorschau anders aus" war immer wahr.
                 $documents = [$document, ...array_values($areas), ...array_values($sections)];
-                $styles = $this->theme->css($theme);
+                $styles = $this->theme->css($theme).$this->menus->buttonCss($theme['buttons']);
                 foreach ($documents as $doc) {
                     $styles .= $this->styles->compileDocument($doc).$this->code->compileDocument($doc);
                 }