Fix blocage asyncio viewfinder + bouton retour sur erreur camera

backend/main.py

@@ -686,11 +686,13 @@ async def traiter_message_ws(msg: dict, ws: WebSocket):
         await ws.send_json({"type": "pong"})
     elif type_msg == "preview_start":
         global _preview_actif
-        camera.activer_viewfinder()
+        loop = asyncio.get_event_loop()
+        await loop.run_in_executor(None, camera.activer_viewfinder)
         _preview_actif = True
     elif type_msg == "preview_stop":
         _preview_actif = False
-        camera.desactiver_viewfinder()
+        loop = asyncio.get_event_loop()
+        asyncio.ensure_future(loop.run_in_executor(None, camera.desactiver_viewfinder))
 
 
 async def diffuser_ws(message: dict):

frontend/index.html

@@ -16,6 +16,7 @@
       <div class="camera-erreur-icon">&#128247;</div>
       <p>Probleme de communication avec l'appareil photo</p>
       <span class="camera-erreur-sub">Reconnexion en cours...</span>
+      <button onclick="document.getElementById('camera-erreur').classList.add('cache'); afficherEcran('accueil')" style="margin-top:2rem;padding:1rem 2rem;font-size:1.5rem;border-radius:1rem;border:none;background:#e91e63;color:#fff;cursor:pointer;">Retour accueil</button>
     </div>
 
     <!-- Ecran d'accueil -->