Make the consent notice styleable and keep the back-to-top button reachable in 1.14.1

The back-to-top button was hidden as long as the consent question was open,
on every device - and on a phone the question tends to stay open. Instead
of `display:none` it now anchors itself 12px above the bar wherever the bar
covers its corner: below 800px for the centred card, at every width for the
full-width bar and the corner card. Browsers without anchor positioning keep
hiding it there. The bar renders before the button so it can be an anchor,
and the reserved bottom padding grows to 320px below 620px, where the bar
with its default text is up to 299px tall.

The notice itself gets a face. Settings → Einwilligung now carries layout
(card, bar, corner), shape (soft, round, square - one setting for the box and
its buttons), a heading and four colours, each as #hex or @palette key.
`Theme::cssColor()` resolves both, replacing the copy inside the back-to-top
code; `Consent::styles()` writes the values as `--kant-consent-*` into the
hashed style block. The base layout changes with it: an accent stripe and
shield icon, equal-width buttons, a disclosure with a chevron, underlined
legal links, a two-column bar on wide screens. Declining stays an outlined
button of the same size next to accepting. The archive and the consent page
carry the same variables - the archive had no palette at all until now.

In the editor, rows with an own value are labelled in orange rather than
bold with a dot; the device chips sit 6px apart with the focus ring inside
the gap.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

templates/page.html.twig

@@ -97,13 +97,15 @@
         {% for block in areas.footer.blocks %}{% include 'blocks/block.html.twig' with {block: block, editing: editing|default(false), postLists: {}, forms: {}, breadcrumbs: [], navigation: navigation|default({}), sections: sections|default({}), richText: areas.footer.schemaVersion|default(1) >= 12, richHeadings: areas.footer.schemaVersion|default(1) >= 17, eagerImage: null} only %}{% endfor %}
     </footer>
     {% endif %}
+    {% if not editing|default(false) and consentGate.needsBanner(app.request) %}
+        {% include 'consent-banner.html.twig' with {consent: consentGate.state(app.request), back: app.request.pathInfo} only %}
+    {% endif %}
+    {# Der Knopf steht hinter der Einwilligungsleiste: Solange sie offen ist, setzt er sich per
+       Ankerpositionierung auf ihre Oberkante, und ein Anker muss im Dokument davor stehen. #}
     {% set oben = siteSettings.load() %}
     {% if oben.scrollTop|default(false) and not editing|default(false) %}
     {# Ein Anker, kein Skript. Er springt an den Anfang - das kann ein Browser allein. #}
     <a class="scroll-top{{ oben.scrollTopPosition|default('rechts') == 'links' ? ' scroll-top-links' : '' }}" href="#seitenanfang" aria-label="{{ oben.scrollTopLabel|default('Nach oben') }}"><span aria-hidden="true">↑</span></a>
     {% endif %}
-    {% if not editing|default(false) and consentGate.needsBanner(app.request) %}
-        {% include 'consent-banner.html.twig' with {consent: consentGate.state(app.request), back: app.request.pathInfo} only %}
-    {% endif %}
 </body>
 </html>