test: check-sizes measures text and control heights per size mode (T8)

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

e2e/size.mjs

@@ -0,0 +1,10 @@
+// Saves a size mode on the logged-in user's account (needs the redmine_tonalmine plugin).
+// No size resets the account to the default appearance.
+export async function setSize(page, size) {
+  const status = await page.evaluate(async (body) => {
+    const headers = { 'Content-Type': 'application/json', 'X-Requested-With': 'XMLHttpRequest',
+      'X-CSRF-Token': document.querySelector('meta[name="csrf-token"]').content };
+    return (await fetch('/tonalmine/appearance', { method: 'PUT', headers, body: JSON.stringify(body) })).status;
+  }, size ? { size } : {});
+  if (status !== 204) throw new Error(`could not save size ${size ?? 'default'} (HTTP ${status})`);
+}