fix: shrink test question heading size

Question text used h2/text-xl, making it stand out more than intended; reduced to h3/text-base in both the weekly theme test and on-demand topic test.

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

src/pages/Testen.jsx

@@ -375,7 +375,7 @@ const Testen = () => {
               <div className="flex items-center gap-2 mb-4">
                 <Tag variant="accent" className="text-xs">{q.topicLabel}</Tag>
               </div>
-              <h2 className="text-xl font-bold leading-snug">{q.question}</h2>
+              <h3 className="text-base font-bold leading-snug">{q.question}</h3>
             </Card>
 
             {/* Options */}

src/pages/TopicTest.jsx

@@ -431,7 +431,7 @@ const TopicTest = () => {
                 <Tag variant="accent" className="text-xs">{pickedTopic?.label}</Tag>
                 {!q.isUnseen && <Tag variant="dark" className="text-[10px]">Practice (no points)</Tag>}
               </div>
-              <h2 className="text-xl font-bold leading-snug">{q.question}</h2>
+              <h3 className="text-base font-bold leading-snug">{q.question}</h3>
             </Card>
 
             <div className="space-y-3">