Translate pages, areas, menus, forms and posts field by field instead of rebuilding them

A site can have further languages (Settings → Languages). A page is built once; each language
adds only its texts, keyed by the stable block IDs, plus its own address under /en/… (ADR 111,
document schema v27, migration 20261009000100 for page_translation).

- Editor: DE | EN switch, a list of all texts with original, state (missing, translated,
  original changed) and filter; structure stays with the main language. Undo, drafts,
  publishing and revisions cover all languages at once.
- Website: /en and translated slugs, lang, canonical, hreflang with x-default, og:locale,
  sitemap; links to translated pages follow the language; a language switch block.
- Header, footer and linked sections translate the same way; menu entries carry labels per
  language; fixed template texts come from a small dictionary.
- Forms: labels, help, options, button and success message per language; messages and the
  step script speak the language, the submission and the email stay in the main language.
- Posts, archives, category names, consent text and the 404 page follow the language.
- Single-language sites see none of it and never touch the new table.

The forms administration becomes an overview with one row per form and its own edit page;
fields are one line each with details collapsed.

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

public/assets/menu-editor.js

@@ -85,6 +85,12 @@ function createRow(data) {
   summary.append(el('strong', 'menu-entry-title', data.label), el('span', 'menu-entry-kind', data.type === 'page' ? 'Seitenlink' : 'Eigener Link'), chevron);
   const body = el('div', 'menu-entry-fields'); details.append(summary, body); row.append(handle, details);
   const label = field('label', data.label, 'Beschriftung'); label.required = true; label.maxLength = 80;
+  // Je weitere Sprache eine eigene Beschriftung (ADR 111); leer zeigt die der Hauptsprache.
+  for (const language of JSON.parse(form.dataset.languages || '[]')) {
+    const translated = field(`label_${language.code}`, data[`label_${language.code}`] ?? data.labels?.[language.code] ?? '', `Beschriftung ${language.name}`);
+    translated.maxLength = 80; translated.lang = language.code; translated.placeholder = `Leer: wie „${data.label}“`;
+    if (language.rtl) translated.dir = 'rtl';
+  }
   if (data.type === 'page') {
     const picker = form.querySelector('.menu-add .content-picker').cloneNode(true); delete picker.dataset.ready;
     const input = picker.querySelector('[role="combobox"]'); input.id = `menu-target-${id}`; input.value = data.pageDisplay || '';