Point 1 : 

As for brief, ask the user confirmation before reporting an answer. 

Point 2 : 

a/ 

In received mail : 

• Update suject. It is not the message but the answer that is reported. 
  • [Espace projet XX] Réponse signalée pour le sujet "XX"
• Remove "Voir dans l'espace de travail" button

b/ Update also mail in english