feat(ui): badge version visible + FAB AI flottant

frontend/locales/en.json

@@ -1599,5 +1599,7 @@
   "bookslm.context_too_large": "Directory too large — some files were truncated",
   "bookslm.source": "Source",
   "palette.bookslm_open": "BooksLM: Open for current directory",
-  "palette.bookslm_new": "BooksLM: New conversation"
+  "palette.bookslm_new": "BooksLM: New conversation",
+  "fab.open": "Open AI assistant",
+  "fab.close": "Close AI assistant"
 }

frontend/locales/fr.json

@@ -1599,5 +1599,7 @@
   "bookslm.context_too_large": "Répertoire trop volumineux — certains fichiers ont été tronqués",
   "bookslm.source": "Source",
   "palette.bookslm_open": "BooksLM: Ouvrir pour le répertoire courant",
-  "palette.bookslm_new": "BooksLM: Nouvelle conversation"
+  "palette.bookslm_new": "BooksLM: Nouvelle conversation",
+  "fab.open": "Ouvrir l'assistant AI",
+  "fab.close": "Fermer l'assistant AI"
 }