feat: filtre de recherche dans la sidebar Historique IA (#98) + menus '@' et '/' depuis le menu '+' (BUG-048)

frontend/locales/en.json

@@ -1544,6 +1544,7 @@
   "sidebar.expand_collapse": "Expand/Collapse",
   "sidebar.file_icons": "Icons",
   "sidebar.filter_instant": "Instant search",
+  "sidebar.filter_ai": "Filter AI history...",
   "sidebar.filter_path": "Path filters",
   "sidebar.filter_placeholder": "Filter files...",
   "sidebar.filter_results_grouped": "Grouped results",
@@ -1826,6 +1827,7 @@
   "bookslm.session_history": "Session history",
   "bookslm.session_delete": "Delete session",
   "bookslm.history_empty": "No saved session",
+  "bookslm.history_no_match": "No conversation matches the search",
   "bookslm.untitled": "Untitled conversation",
   "bookslm.no_vault": "No active vault to open this link",
   "bookslm.copied_name": "Name copied: {name}",

frontend/locales/fr.json

@@ -1544,6 +1544,7 @@
   "sidebar.expand_collapse": "Développer/Réduire",
   "sidebar.file_icons": "Icônes",
   "sidebar.filter_instant": "Recherche instantanée",
+  "sidebar.filter_ai": "Filtrer l'historique IA...",
   "sidebar.filter_path": "Filtres de chemin",
   "sidebar.filter_placeholder": "Filtrer fichiers...",
   "sidebar.filter_results_grouped": "Résultats groupés",
@@ -1826,6 +1827,7 @@
   "bookslm.session_history": "Historique des sessions",
   "bookslm.session_delete": "Supprimer la session",
   "bookslm.history_empty": "Aucune session enregistrée",
+  "bookslm.history_no_match": "Aucune conversation ne correspond à la recherche",
   "bookslm.untitled": "Conversation sans titre",
   "bookslm.no_vault": "Aucun vault actif pour ouvrir ce lien",
   "bookslm.copied_name": "Nom copié : {name}",