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>

templates/blocks/form.html.twig

@@ -3,13 +3,14 @@
    Schritt nach dem anderen. Bedingungen stehen als Datenattribute am Feld; der Server prüft sie
    beim Absenden selbst und verlangt nichts, was gar nicht galt. #}
 {% if form is null %}
-    <p class="form-missing">Dieses Formular ist nicht mehr vorhanden.</p>
+    <p class="form-missing">{{ 'Dieses Formular ist nicht mehr vorhanden.'|kant_t }}</p>
 {% elseif sent %}
-    <p class="form-success" role="status">{{ form.settings.success }}</p>
+    <p class="form-success" role="status">{{ form.settings.success|kant_t }}</p>
 {% else %}
 {% set hasSteps = form.fields|filter(f => f.type == 'step')|length > 0 %}
-<form class="block-form{{ hasSteps ? ' form-stepped' : '' }}" data-form="{{ form.slug }}" method="post" action="{{ path('form_submit', {slug: form.slug}) }}" novalidate{% if hasSteps %} data-steps{% endif %}{% if form.settings.summary|default(false) %} data-summary{% endif %}>
+<form class="block-form{{ hasSteps ? ' form-stepped' : '' }}" data-form="{{ form.slug }}" method="post" action="{{ path('form_submit', {slug: form.slug}) }}" novalidate{% if hasSteps %} data-steps{% endif %}{% if form.settings.summary|default(false) %} data-summary{% endif %}{% if form.locale|default(null) %} data-texts="{{ {summary: 'Zusammenfassung'|kant_t, summaryIntro: 'Bitte prüfen Sie Ihre Angaben. Über „Ändern“ kommen Sie zum jeweiligen Schritt zurück.'|kant_t, steps: 'Schritte des Formulars'|kant_t, step: 'Schritt'|kant_t, back: 'Zurück'|kant_t, next: 'Weiter'|kant_t, change: 'Ändern'|kant_t, yes: 'Ja'|kant_t, chooseOne: 'Bitte wähle mindestens eine Option.'|kant_t}|json_encode|e('html_attr') }}"{% endif %}>
     <input type="hidden" name="page" value="{{ page.path }}">
+    {% if form.locale|default(null) %}<input type="hidden" name="language" value="{{ form.locale }}">{% endif %}
     <input type="hidden" name="block" value="{{ blockId }}">
     <input type="hidden" name="issued" value="{{ issued }}">
     <input type="hidden" name="issuedSignature" value="{{ issuedSignature }}">
@@ -17,7 +18,7 @@
     <div class="form-trap" aria-hidden="true"><label for="website-{{ blockId }}">Website</label><input id="website-{{ blockId }}" name="website" type="text" tabindex="-1" autocomplete="off"></div>
 
     {% if errors is not empty %}
-    <p class="form-error-summary" role="alert">Bitte prüfe {{ errors|length }} {{ errors|length == 1 ? 'Eingabe' : 'Eingaben' }}. Die betroffenen Felder sind unten gekennzeichnet.</p>
+    <p class="form-error-summary" role="alert">{{ (errors|length == 1 ? 'Bitte prüfe 1 Eingabe. Die betroffenen Felder sind unten gekennzeichnet.' : 'Bitte prüfe %d Eingaben. Die betroffenen Felder sind unten gekennzeichnet.')|kant_t|format(errors|length) }}</p>
     {% endif %}
 
     {% for field in form.fields %}
@@ -26,7 +27,7 @@
         {% set value = values[field.name]|default('') %}
         {% set described = (field.help ? id ~ '-help ' : '') ~ (error ? id ~ '-error' : '') %}
         {% set condition %}{% if field.showIf|default(null) %} data-show-if="{{ field.showIf.field }}" data-show-values="{{ field.showIf.values|join('|') }}"{% endif %}{% endset %}
-        {% set requiredMark %}{% if field.required %} <span class="required-mark" aria-hidden="true">*</span><span class="visually-hidden"> (Pflichtfeld)</span>{% endif %}{% endset %}
+        {% set requiredMark %}{% if field.required %} <span class="required-mark" aria-hidden="true">*</span><span class="visually-hidden"> ({{ 'Pflichtfeld'|kant_t }})</span>{% endif %}{% endset %}
         {% if field.type == 'step' %}
             {% if not loop.first and form.fields[0:loop.index0]|filter(f => f.type == 'step')|length > 0 %}</fieldset>{% endif %}
             <fieldset class="form-step" data-step{{ condition }}>
@@ -58,7 +59,7 @@
                 {% set bild = optionImages[field.images[option]|default('')]|default(null) %}
                 <div class="{{ bildauswahl ? 'form-choice-card' : 'check-row' }}">
                     <input id="{{ id }}-{{ loop.index }}" name="{{ field.name }}{{ field.type == 'checkboxes' ? '[]' : '' }}" type="{{ field.type == 'checkboxes' ? 'checkbox' : 'radio' }}" value="{{ option }}"{{ option in picked ? ' checked' : '' }}{{ field.type == 'radio' and field.required ? ' required' : '' }}{{ error ? ' aria-invalid="true"' : '' }}>
-                    <label for="{{ id }}-{{ loop.index }}">{% if bildauswahl %}<span class="form-choice-picture">{% if bild %}<img src="{{ bild.src }}" alt="" width="{{ bild.width }}" height="{{ bild.height }}" loading="lazy" decoding="async">{% endif %}</span><span class="form-choice-text">{{ option }}</span>{% else %}{{ option }}{% endif %}</label>
+                    <label for="{{ id }}-{{ loop.index }}">{% if bildauswahl %}<span class="form-choice-picture">{% if bild %}<img src="{{ bild.src }}" alt="" width="{{ bild.width }}" height="{{ bild.height }}" loading="lazy" decoding="async">{% endif %}</span><span class="form-choice-text">{{ field.optionLabels[option]|default(option) }}</span>{% else %}{{ field.optionLabels[option]|default(option) }}{% endif %}</label>
                 </div>
                 {% endfor %}
                 {% if bildauswahl %}</div>{% endif %}
@@ -67,15 +68,15 @@
             </fieldset>
         {% else %}
             <div class="form-field{{ error ? ' has-error' : '' }}" data-field data-label="{{ field.label }}"{{ condition }}>
-                <label for="{{ id }}">{{ field.label }}{{ requiredMark }}{% if field.unit|default('') %}<span class="visually-hidden"> in {{ field.unit }}</span>{% endif %}</label>
+                <label for="{{ id }}">{{ field.label }}{{ requiredMark }}{% if field.unit|default('') %}<span class="visually-hidden"> {{ 'in'|kant_t }} {{ field.unit }}</span>{% endif %}</label>
                 {% if field.type == 'textarea' %}
                     <textarea id="{{ id }}" name="{{ field.name }}" rows="6" maxlength="5000"{{ field.required ? ' required' : '' }}
                               {% if described|trim %}aria-describedby="{{ described|trim }}"{% endif %}{{ error ? ' aria-invalid="true"' : '' }}>{{ value }}</textarea>
                 {% elseif field.type == 'select' %}
                     <select id="{{ id }}" name="{{ field.name }}"{{ field.required ? ' required' : '' }}
                             {% if described|trim %}aria-describedby="{{ described|trim }}"{% endif %}{{ error ? ' aria-invalid="true"' : '' }}>
-                        <option value="">— bitte wählen —</option>
-                        {% for option in field.options %}<option value="{{ option }}"{{ value == option ? ' selected' : '' }}>{{ option }}</option>{% endfor %}
+                        <option value="">— {{ 'bitte wählen'|kant_t }} —</option>
+                        {% for option in field.options %}<option value="{{ option }}"{{ value == option ? ' selected' : '' }}>{{ field.optionLabels[option]|default(option) }}</option>{% endfor %}
                     </select>
                 {% elseif field.type == 'number' %}
                     <div class="form-number{{ field.unit|default('') ? ' has-unit' : '' }}">
@@ -101,10 +102,10 @@
     {% if turnstileKey|default('') %}
     {# Cloudflare Turnstile. Braucht JavaScript; ohne Skript bleibt das Formular unabsendbar, und
        genau deshalb ist die Prüfung eine Entscheidung und keine Voreinstellung. #}
-    <div class="cf-turnstile" data-sitekey="{{ turnstileKey }}" data-language="de"></div>
-    <noscript><p class="field-error">Zum Absenden dieses Formulars wird JavaScript benötigt. Schreib uns sonst gern direkt eine E-Mail.</p></noscript>
+    <div class="cf-turnstile" data-sitekey="{{ turnstileKey }}" data-language="{{ form.locale|default('de') }}"></div>
+    <noscript><p class="field-error">{{ 'Zum Absenden dieses Formulars wird JavaScript benötigt. Schreib uns sonst gern direkt eine E-Mail.'|kant_t }}</p></noscript>
     <script src="https://challenges.cloudflare.com/turnstile/v0/api.js" async defer></script>
     {% endif %}
-    <button class="button cms-button" type="submit">{{ form.settings.buttonLabel|default('Absenden') }}</button>
+    <button class="button cms-button" type="submit">{{ form.settings.buttonLabel|default('Absenden')|kant_t }}</button>
 </form>
 {% endif %}