Raise loaded documents to the schema their blocks need, and bring the old browser checks back

The kant-it.de header used the hamburger switch at schema 19, so the server refused its
preview and save; the editor now raises a loaded document to the version its blocks and
properties require. The admin, button and navigation checks select blocks through the
structure tab, find the motion button by id and expect what the site's motion setting says.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

scripts/button-check.mjs

@@ -30,6 +30,13 @@ try {
   browser = await chromium.launch();
   const context = await browser.newContext({ viewport: { width: 1600, height: 1050 } });
   page = await context.newPage(); page.setDefaultTimeout(15000); page.on('pageerror', error => errors.push(error.message));
+  // Ein Baustein wird im Reiter „Struktur“ gewählt und mit „Bearbeiten“ geöffnet - die
+  // Seitenleiste zeigt seit 1.11 nur eine Ansicht auf einmal.
+  const selectBlock = async id => {
+    await page.getByRole('tab', { name: 'Struktur', exact: true }).click();
+    await page.locator(`#structure [data-block-id="${id}"]`).click();
+    await page.locator(`#structure [data-edit-block="${id}"]`).click();
+  };
   await page.goto(origin + '/admin/login');
   await page.getByLabel('Benutzername').fill(fixture.username); await page.getByLabel('Passwort', { exact: true }).fill(fixture.password);
   await page.getByRole('button', { name: 'Anmelden', exact: true }).click(); await page.waitForURL(origin + '/admin');
@@ -53,7 +60,7 @@ try {
   checks.push('global typography, visual presets, normal/hover preview and actual form save including empty palette rows');
 
   await page.goto(`${origin}/admin/pages/${fixture.homeId}`);
-  await page.locator('#structure [data-block-id="qa-button"]').click();
+  await selectBlock('qa-button');
   await page.getByRole('button', { name: 'Button-Vorlage Abgerundet', exact: true }).click();
   const waitVariant = async (id, radius, background) => page.waitForFunction(({id,radius,background}) => {
     const doc = document.querySelector('#preview')?.contentDocument, el = doc?.getElementById(id);
@@ -75,7 +82,7 @@ try {
   await page.locator('[data-viewport="desktop"]').click(); await waitVariant('qa-button', '8px', false);
   await page.locator('.button-designer').screenshot({ path: `${report}/editor-controls.png` });
   await page.locator('#save').click(); await page.locator('#save-status').filter({ hasText: 'Entwurf gespeichert' }).waitFor();
-  await page.reload(); await page.locator('#structure [data-block-id="qa-button"]').click(); await waitVariant('qa-button', '8px', false);
+  await page.reload(); await selectBlock('qa-button'); await waitVariant('qa-button', '8px', false);
   const stored = (await (await context.request.get(api)).json()).document;
   assert.equal(stored.schemaVersion, 21);
   assert.deepEqual(stored.blocks[0].children[1].props, { text: 'Mehr erfahren', href: '/kontakt' });