fix: raw i18n keys + truncated paragraphs in Navigation section

- Added missing help.desc_filter_usage + help.desc_vault_context keys
- Fixed truncated auto paragraphs (full text now in locale)
- All truncated paragraphs restored to complete text

frontend/locales/en.json

@@ -935,5 +935,7 @@
   "help.desc_chip_view": ": See active filters at a glance",
   "help.desc_chip_remove": ": Click \"×\" to remove a filter",
   "help.desc_facet_vaults": ": Counters by vault",
-  "help.access": "Access"
+  "help.access": "Access",
+  "help.desc_filter_usage": "Use the filter bar at the top of the sidebar to search quickly:",
+  "help.desc_vault_context": "Change context to filter the display:"
 }

frontend/locales/fr.json

@@ -935,5 +935,7 @@
   "help.desc_chip_view": ": Voir d'un coup d'œil les filtres actifs",
   "help.desc_chip_remove": ": Cliquez sur \"×\" pour retirer un filtre",
   "help.desc_facet_vaults": ": Compteurs par vault",
-  "help.access": "Accès"
+  "help.access": "Accès",
+  "help.desc_filter_usage": "Utilisez la barre de filtrage en haut de la sidebar pour rechercher rapidement :",
+  "help.desc_vault_context": "Changez de contexte pour filtrer l'affichage :"
 }