The difficulty screen drops its LAST too, and the class with it

It was the last place still breaking the wizard's own rule — a question screen
carries no memory of its own answer. Three names, three pip counts, nothing
else. `.last` has no users left, so the rule is gone from the stylesheet.

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

src/main.js

@@ -157,9 +157,10 @@ function buildSub(top) {
   if (t.diffs) DIFFS.forEach((d, i) => {
     const b = document.createElement('button');
     b.className = 'chip' + (i === DIFFS.length - 1 ? ' hot' : '');
+    // no LAST chip here either (Oliver): a question screen carries no memory of its own answer —
+    // the wizard's own rule, applied to the last screen that was still breaking it
     b.innerHTML = `<b>${d.name}</b><span class="pips">`
-      + [0, 1, 2].map(k => `<i${k <= i ? ' class="on"' : ''}></i>`).join('') + '</span>'
-      + (d.id === pickedDiff ? '<u class="last">LAST</u>' : '');
+      + [0, 1, 2].map(k => `<i${k <= i ? ' class="on"' : ''}></i>`).join('') + '</span>';
     b.addEventListener('click', () => {
       pickedDiff = d.id;
       try { localStorage.setItem('diff', d.id); } catch {}