feat: chat — saisie auto-agrandissante, accusé de réception ✓✓, vignette de tuile #192 (BUG-109)

frontend/locales/en.json

@@ -333,9 +333,12 @@
   "chat.new_message": "New message from {user}",
   "chat.placeholder": "Write a message…",
   "chat.placeholder_dm": "Private message to {user}…",
+  "chat.read_by": "{user} read your message",
   "chat.send": "Send",
   "chat.send_error": "Failed to send the message",
   "chat.tab": "General chat",
+  "chat.status_read": "Read",
+  "chat.status_sent": "Sent",
   "chat.title": "Discussion",
   "common.actions": "Actions",
   "common.all": "All",

frontend/locales/fr.json

@@ -333,9 +333,12 @@
   "chat.new_message": "Nouveau message de {user}",
   "chat.placeholder": "Écrire un message…",
   "chat.placeholder_dm": "Message privé à {user}…",
+  "chat.read_by": "{user} a lu votre message",
   "chat.send": "Envoyer",
   "chat.send_error": "Échec de l'envoi du message",
   "chat.tab": "Chat général",
+  "chat.status_read": "Lu",
+  "chat.status_sent": "Envoyé",
   "chat.title": "Discussion",
   "common.actions": "Actions",
   "common.all": "Tous",