- 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>