feat(users): show last-access timestamp per user

Maps Navidrome's lastAccessAt onto NdUser and renders it in the
User Management row as a localized relative time (Intl.RelativeTimeFormat
with the current i18n language). Tooltip carries the absolute
timestamp. Navidrome returns 0001-01-01 for never-accessed users —
detected and shown as the localized "Never" label.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/locales/de.ts

@@ -489,6 +489,7 @@ export const deTranslation = {
     userMgmtLibrariesValidation: 'Mindestens eine Bibliothek auswählen.',
     userMgmtLibrariesUpdateError: 'Benutzer gespeichert, aber Bibliothekszuweisung fehlgeschlagen',
     userMgmtNoLibraries: 'Keine Bibliotheken zugewiesen',
+    userMgmtNeverSeen: 'Nie',
     userMgmtSave: 'Speichern',
     userMgmtCancel: 'Abbrechen',
     userMgmtDelete: 'Löschen',

src/locales/en.ts

@@ -491,6 +491,7 @@ export const enTranslation = {
     userMgmtLibrariesValidation: 'Select at least one library.',
     userMgmtLibrariesUpdateError: 'User saved, but library assignment failed',
     userMgmtNoLibraries: 'No libraries assigned',
+    userMgmtNeverSeen: 'Never',
     userMgmtSave: 'Save',
     userMgmtCancel: 'Cancel',
     userMgmtDelete: 'Delete',

src/locales/es.ts

@@ -482,6 +482,7 @@ export const esTranslation = {
     userMgmtLibrariesValidation: 'Selecciona al menos una biblioteca.',
     userMgmtLibrariesUpdateError: 'Usuario guardado, pero la asignación de bibliotecas falló',
     userMgmtNoLibraries: 'Sin bibliotecas asignadas',
+    userMgmtNeverSeen: 'Nunca',
     userMgmtSave: 'Guardar',
     userMgmtCancel: 'Cancelar',
     userMgmtDelete: 'Eliminar',

src/locales/fr.ts

@@ -479,6 +479,7 @@ export const frTranslation = {
     userMgmtLibrariesValidation: 'Sélectionnez au moins une bibliothèque.',
     userMgmtLibrariesUpdateError: 'Utilisateur enregistré, mais l\u2019attribution des bibliothèques a échoué',
     userMgmtNoLibraries: 'Aucune bibliothèque attribuée',
+    userMgmtNeverSeen: 'Jamais',
     userMgmtSave: 'Enregistrer',
     userMgmtCancel: 'Annuler',
     userMgmtDelete: 'Supprimer',

src/locales/nb.ts

@@ -479,6 +479,7 @@ export const nbTranslation = {
     userMgmtLibrariesValidation: 'Velg minst ett bibliotek.',
     userMgmtLibrariesUpdateError: 'Brukeren ble lagret, men bibliotekstilordning mislyktes',
     userMgmtNoLibraries: 'Ingen biblioteker tilordnet',
+    userMgmtNeverSeen: 'Aldri',
     userMgmtSave: 'Lagre',
     userMgmtCancel: 'Avbryt',
     userMgmtDelete: 'Slett',

src/locales/nl.ts

@@ -478,6 +478,7 @@ export const nlTranslation = {
     userMgmtLibrariesValidation: 'Selecteer ten minste één bibliotheek.',
     userMgmtLibrariesUpdateError: 'Gebruiker opgeslagen, maar bibliotheektoewijzing mislukt',
     userMgmtNoLibraries: 'Geen bibliotheken toegewezen',
+    userMgmtNeverSeen: 'Nooit',
     userMgmtSave: 'Opslaan',
     userMgmtCancel: 'Annuleren',
     userMgmtDelete: 'Verwijderen',

src/locales/ru.ts

@@ -496,6 +496,7 @@ export const ruTranslation = {
     userMgmtLibrariesValidation: 'Выберите хотя бы одну библиотеку.',
     userMgmtLibrariesUpdateError: 'Пользователь сохранён, но не удалось назначить библиотеки',
     userMgmtNoLibraries: 'Библиотеки не назначены',
+    userMgmtNeverSeen: 'Никогда',
     userMgmtSave: 'Сохранить',
     userMgmtCancel: 'Отмена',
     userMgmtDelete: 'Удалить',

src/locales/zh.ts

@@ -474,6 +474,7 @@ export const zhTranslation = {
     userMgmtLibrariesValidation: '请至少选择一个音乐库。',
     userMgmtLibrariesUpdateError: '用户已保存，但音乐库分配失败',
     userMgmtNoLibraries: '未分配音乐库',
+    userMgmtNeverSeen: '从未',
     userMgmtSave: '保存',
     userMgmtCancel: '取消',
     userMgmtDelete: '删除',