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/editor.css

@@ -285,3 +285,35 @@ html:has(>.editor-body){overflow:hidden;height:100%}
   .canvas-panel{height:62vh;flex:none}.sidebar{height:62vh;flex:none;border-right:0;border-top:1px solid var(--line)}
   .library-buttons{grid-template-columns:repeat(4,minmax(0,1fr))}
 }
+/* Übersetzen (ADR 111). Der Umschalter sitzt neben der Vorschaugröße; im Übersetzungsmodus
+   verschwindet alles, was den Aufbau ändert - Reiter, Blockaktionen, Werkzeuge der Vorschau. */
+.language-switch{display:flex;gap:2px;padding:3px;background:#ffffff14;border-radius:9px}
+.language-switch[hidden]{display:none}
+.language-switch button{border:0;background:transparent;color:#c9d4cd;padding:0 10px;min-height:30px;min-width:36px;border-radius:6px;font-size:12px;font-weight:700;letter-spacing:.04em}
+.language-switch button:hover:not(:disabled){color:#fff}
+.editor-header .language-switch button[aria-pressed=true]{background:#fff;color:var(--ink)}
+#editor[data-language] .language-switch button[aria-pressed=true]{background:#f5c451;color:#1d1d1b}
+#editor[data-language] .sidebar-nav,#editor[data-language] .sidebar-foot,#editor[data-language] .ov-toolbar,#editor[data-language] .ov-insert,#editor[data-language] .ov-resize,#editor[data-language] .ov-drop{display:none!important}
+.translate-head{display:grid;gap:8px;margin-bottom:16px}
+.translate-head h2{margin:0;font-size:16px}
+.translate-head h2:focus{outline:none}
+.translate-head progress{width:100%;height:8px;accent-color:var(--ink)}
+.translate-summary{margin:0;font-size:13px;font-weight:600}
+.translate-group{border-top:1px solid var(--line,#dfe5e1);padding:12px 0 4px;scroll-margin-top:12px}
+.translate-group.is-current{box-shadow:inset 3px 0 0 #f5c451;padding-left:10px}
+.translate-group h3{margin:0 0 8px;font-size:13px}
+.translate-jump{border:0;background:none;padding:0;font:inherit;font-weight:700;color:inherit;text-align:left;cursor:pointer}
+.translate-jump:hover{text-decoration:underline}
+.translate-field{display:grid;gap:5px;margin-bottom:14px}
+.translate-field-head{display:flex;justify-content:space-between;align-items:baseline;gap:8px}
+.translate-field-head label{margin:0}
+.translate-state{font-size:11px;font-weight:700;padding:2px 7px;border-radius:999px;background:#e8ece9;color:#384640;white-space:nowrap}
+.translate-field[data-state=missing] .translate-state{background:#fde9c8;color:#6b3f00}
+.translate-field[data-state=stale] .translate-state{background:#fbd5d0;color:#7a1d12}
+.translate-field[data-state=done] .translate-state{background:#d7eedf;color:#1c5233}
+.translate-original{margin:0;padding:6px 8px;border-radius:6px;background:#f2f4f3;color:#46514c;font-size:12.5px;line-height:1.45;white-space:pre-line;max-height:7.5em;overflow:auto}
+.translate-actions{display:flex;gap:12px;flex-wrap:wrap}
+.translate-slug{display:flex;align-items:center;gap:4px}
+.translate-slug input{flex:1;min-width:0}
+.translate-prefix{font-size:12px;color:#5b6862;white-space:nowrap}
+.translate-filter{margin-top:4px}