Surprise + capture en parallele : DSLR declenche pendant l'image surprise

- Preview stoppe AVANT la surprise (plus de frame flou)
- Capture DSLR lancee en meme temps que la surprise (apiPost en parallele)
- 800ms de reaction pendant que le DSLR travaille
- Flash + masquer surprise apres le declenchement

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

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