feat: Ultrafast preset for all modules, Text Story margin fix, Quiz Explain box improvements

feat: Major optimizations - Quiz dynamic fonts, TTS 1.2x speed, Video stream copy (10x faster), Single API call, Fact Image dynamic fonts, Text Story position fix

Smooth beep sound with fade-in/fade-out envelope

Explanation heading 52px, beep 6% volume

Move Explanation to midpoint, bigger font, beep 15%

Fix countdown centering, bigger circle, quieter beep, add Explanation heading

Add 3-2-1 countdown timer with beep sounds during thinking phase

Add hook padding, golden explain color, auto-sizing centered question text

Improve quiz design: hook bg box #ab0042, larger explain text, remove sparkle

Add Quiz Reel module with TTS, frame generation, and video composition