feat: remove header row, add unlock gate + ring animation to Satz card

- Remove lang/points header from all 3 card types
- PairSentenceCard: Verstanden button locked until audio played OR
  translate button held for 2 seconds
- Hold button shows circular gold ring filling up over 2s while held
- TTS button highlights gold when unlocked
- .pair-btn-locked style for disabled state

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/PairWordCard.jsx

@@ -139,17 +139,7 @@ export default function PairWordCard({ card, onComplete }) {
         {isObject && <SelectionOverlay chip={activeChip} />}
       </div>
 
-      {/* Header below image */}
-      <div className="pair-card-header">
-        <span className="pair-lang-pill">{lang === 'sv' ? 'Svenska' : lang === 'en' ? 'English' : 'Deutsch'}</span>
-        <span className="pair-points-pill">
-          <svg width="13" height="13" viewBox="0 0 24 24" fill="#C4A85A"><path d="M12 2l3.09 6.26L22 9.27l-5 4.87 1.18 6.88L12 17.77l-6.18 3.25L7 14.14 2 9.27l6.91-1.01L12 2z"/></svg>
-          +{card.meta?.points ?? 3} Punkte
-        </span>
-      </div>
-      <div className="pair-header-divider" />
-
-      <div className="pair-card-body" onClick={e => e.stopPropagation()}>
+      <div className="pair-card-body" onClick={e => e.stopPropagation()} style={{ paddingTop: 18 }}>
         <p className="pair-section-label">Frage</p>
         <p className="pair-question">
           {resolveSentence(sentence, card.placeholders, handleChipClick, activeChip?.id)}