feat(settings): add "Refresh cached data" recovery action

When the mailbox view gets into a stale or wrong state, the only escape
was the browser's "clear site data" — which also wipes the saved account
list, forcing a re-login of every account.

Add a non-destructive "Refresh cached data" button under Settings →
Data. It clears the server-derived caches (contacts, calendars,
identities, per-account snapshots) and reloads so they re-fetch fresh,
while preserving accounts, sessions, settings, themes and user content
(templates, S/MIME). Two-click confirm to avoid an accidental reload.

English strings added across all locales (translation follow-up); unit
tests cover the cache-clear (keeps account-registry/auth/prefs) and the
reload.

locales/cs/common.json

@@ -1628,6 +1628,11 @@
         "description": "Zobrazit dostupné klávesové zkratky",
         "button": "Zobrazit zkratky"
       },
+      "refresh_cache": {
+        "label": "Refresh cached data",
+        "description": "Reload contacts, calendars, and folders from the server. Keeps your accounts and sessions \u2014 fixes a stale or wrong view without signing out.",
+        "button": "Refresh"
+      },
       "reset_settings": {
         "label": "Resetovat nastavení",
         "description": "Obnovit všechna nastavení na výchozí hodnoty",

locales/da/common.json

@@ -1631,6 +1631,11 @@
         "description": "Se tilgængelige tastaturgenveje",
         "button": "Vis genveje"
       },
+      "refresh_cache": {
+        "label": "Refresh cached data",
+        "description": "Reload contacts, calendars, and folders from the server. Keeps your accounts and sessions \u2014 fixes a stale or wrong view without signing out.",
+        "button": "Refresh"
+      },
       "reset_settings": {
         "label": "Nulstil indstillinger",
         "description": "Gendan alle indstillinger til standardværdier",

locales/de/common.json

@@ -1628,6 +1628,11 @@
         "description": "Verfügbare Tastaturkürzel anzeigen",
         "button": "Tastaturkürzel anzeigen"
       },
+      "refresh_cache": {
+        "label": "Refresh cached data",
+        "description": "Reload contacts, calendars, and folders from the server. Keeps your accounts and sessions \u2014 fixes a stale or wrong view without signing out.",
+        "button": "Refresh"
+      },
       "reset_settings": {
         "label": "Einstellungen zurücksetzen",
         "description": "Alle Einstellungen auf Standardwerte zurücksetzen",

locales/en/common.json

@@ -1637,6 +1637,11 @@
         "description": "View available keyboard shortcuts",
         "button": "View Shortcuts"
       },
+      "refresh_cache": {
+        "label": "Refresh cached data",
+        "description": "Reload contacts, calendars, and folders from the server. Keeps your accounts and sessions \u2014 fixes a stale or wrong view without signing out.",
+        "button": "Refresh"
+      },
       "reset_settings": {
         "label": "Reset Settings",
         "description": "Restore all settings to default values",

locales/es/common.json

@@ -1628,6 +1628,11 @@
         "description": "Ver atajos de teclado disponibles",
         "button": "Ver Atajos"
       },
+      "refresh_cache": {
+        "label": "Refresh cached data",
+        "description": "Reload contacts, calendars, and folders from the server. Keeps your accounts and sessions \u2014 fixes a stale or wrong view without signing out.",
+        "button": "Refresh"
+      },
       "reset_settings": {
         "label": "Restablecer Configuración",
         "description": "Restaurar toda la configuración a los valores predeterminados",

locales/fa/common.json

@@ -1635,6 +1635,11 @@
         "description": "مشاهده میانبرهای صفحه کلید موجود",
         "button": "مشاهده میانبرها"
       },
+      "refresh_cache": {
+        "label": "Refresh cached data",
+        "description": "Reload contacts, calendars, and folders from the server. Keeps your accounts and sessions \u2014 fixes a stale or wrong view without signing out.",
+        "button": "Refresh"
+      },
       "reset_settings": {
         "label": "بازنشانی تنظیمات",
         "description": "بازگردانی همه تنظیمات به مقادیر پیش‌فرض",

locales/fr/common.json

@@ -1628,6 +1628,11 @@
         "description": "Voir les raccourcis clavier disponibles",
         "button": "Voir les raccourcis"
       },
+      "refresh_cache": {
+        "label": "Refresh cached data",
+        "description": "Reload contacts, calendars, and folders from the server. Keeps your accounts and sessions \u2014 fixes a stale or wrong view without signing out.",
+        "button": "Refresh"
+      },
       "reset_settings": {
         "label": "Réinitialiser les paramètres",
         "description": "Restaurer tous les paramètres par défaut",

locales/hu/common.json

@@ -1631,6 +1631,11 @@
         "description": "Elérhető billentyűparancsok megtekintése",
         "button": "Parancsok megtekintése"
       },
+      "refresh_cache": {
+        "label": "Refresh cached data",
+        "description": "Reload contacts, calendars, and folders from the server. Keeps your accounts and sessions \u2014 fixes a stale or wrong view without signing out.",
+        "button": "Refresh"
+      },
       "reset_settings": {
         "label": "Beállítások visszaállítása",
         "description": "Összes beállítás visszaállítása az alapértelmezett értékekre",

locales/it/common.json

@@ -1628,6 +1628,11 @@
         "description": "Visualizza le scorciatoie da tastiera disponibili",
         "button": "Visualizza scorciatoie"
       },
+      "refresh_cache": {
+        "label": "Refresh cached data",
+        "description": "Reload contacts, calendars, and folders from the server. Keeps your accounts and sessions \u2014 fixes a stale or wrong view without signing out.",
+        "button": "Refresh"
+      },
       "reset_settings": {
         "label": "Ripristina impostazioni",
         "description": "Ripristina tutte le impostazioni ai valori predefiniti",

locales/ja/common.json

@@ -1628,6 +1628,11 @@
         "description": "利用可能なキーボードショートカットを表示",
         "button": "ショートカットを表示"
       },
+      "refresh_cache": {
+        "label": "Refresh cached data",
+        "description": "Reload contacts, calendars, and folders from the server. Keeps your accounts and sessions \u2014 fixes a stale or wrong view without signing out.",
+        "button": "Refresh"
+      },
       "reset_settings": {
         "label": "設定をリセット",
         "description": "すべての設定をデフォルト値に戻す",

locales/ko/common.json

@@ -1628,6 +1628,11 @@
         "description": "사용 가능한 키보드 단축키를 확인해 보세요",
         "button": "단축키 보기"
       },
+      "refresh_cache": {
+        "label": "Refresh cached data",
+        "description": "Reload contacts, calendars, and folders from the server. Keeps your accounts and sessions \u2014 fixes a stale or wrong view without signing out.",
+        "button": "Refresh"
+      },
       "reset_settings": {
         "label": "설정 초기화",
         "description": "모든 설정을 기본값으로 되돌려요",

locales/lv/common.json

@@ -1609,6 +1609,11 @@
         "description": "Skatīt pieejamos tastatūras īsinājumtaustiņus",
         "button": "Rādīt īsinājumtaustiņus"
       },
+      "refresh_cache": {
+        "label": "Refresh cached data",
+        "description": "Reload contacts, calendars, and folders from the server. Keeps your accounts and sessions \u2014 fixes a stale or wrong view without signing out.",
+        "button": "Refresh"
+      },
       "reset_settings": {
         "label": "Atiestatīt iestatījumus",
         "description": "Atjaunot visus iestatījumus uz noklusējuma vērtībām",

locales/nl/common.json

@@ -1628,6 +1628,11 @@
         "description": "Bekijk beschikbare sneltoetsen",
         "button": "Sneltoetsen bekijken"
       },
+      "refresh_cache": {
+        "label": "Refresh cached data",
+        "description": "Reload contacts, calendars, and folders from the server. Keeps your accounts and sessions \u2014 fixes a stale or wrong view without signing out.",
+        "button": "Refresh"
+      },
       "reset_settings": {
         "label": "Instellingen resetten",
         "description": "Herstel alle instellingen naar standaardwaarden",

locales/pl/common.json

@@ -1628,6 +1628,11 @@
         "description": "Wyświetl dostępne skróty klawiszowe",
         "button": "Pokaż skróty"
       },
+      "refresh_cache": {
+        "label": "Refresh cached data",
+        "description": "Reload contacts, calendars, and folders from the server. Keeps your accounts and sessions \u2014 fixes a stale or wrong view without signing out.",
+        "button": "Refresh"
+      },
       "reset_settings": {
         "label": "Resetuj ustawienia",
         "description": "Przywróć wszystkie ustawienia do wartości domyślnych",

locales/pt/common.json

@@ -1628,6 +1628,11 @@
         "description": "Visualizar atalhos de teclado disponíveis",
         "button": "Ver Atalhos"
       },
+      "refresh_cache": {
+        "label": "Refresh cached data",
+        "description": "Reload contacts, calendars, and folders from the server. Keeps your accounts and sessions \u2014 fixes a stale or wrong view without signing out.",
+        "button": "Refresh"
+      },
       "reset_settings": {
         "label": "Redefinir Configurações",
         "description": "Restaurar todas as configurações para valores padrão",

locales/ro/common.json

@@ -1635,6 +1635,11 @@
         "description": "Vedeți comenzile rapide de la tastatură disponibile",
         "button": "Comenzi rapide de vizualizare"
       },
+      "refresh_cache": {
+        "label": "Refresh cached data",
+        "description": "Reload contacts, calendars, and folders from the server. Keeps your accounts and sessions \u2014 fixes a stale or wrong view without signing out.",
+        "button": "Refresh"
+      },
       "reset_settings": {
         "label": "Resetare setări",
         "description": "Restabiliți toate setările la valorile implicite",

locales/ru/common.json

@@ -1628,6 +1628,11 @@
         "description": "Просмотреть доступные сочетания клавиш",
         "button": "Показать сочетания"
       },
+      "refresh_cache": {
+        "label": "Refresh cached data",
+        "description": "Reload contacts, calendars, and folders from the server. Keeps your accounts and sessions \u2014 fixes a stale or wrong view without signing out.",
+        "button": "Refresh"
+      },
       "reset_settings": {
         "label": "Сбросить настройки",
         "description": "Восстановить все настройки до значений по умолчанию",

locales/tr/common.json

@@ -1628,6 +1628,11 @@
         "description": "Mevcut klavye kısayollarını görüntüleyin",
         "button": "Kısayolları Görüntüle"
       },
+      "refresh_cache": {
+        "label": "Refresh cached data",
+        "description": "Reload contacts, calendars, and folders from the server. Keeps your accounts and sessions \u2014 fixes a stale or wrong view without signing out.",
+        "button": "Refresh"
+      },
       "reset_settings": {
         "label": "Ayarları Sıfırla",
         "description": "Tüm ayarları varsayılan değerlerine geri yükle",

locales/uk/common.json

@@ -1628,6 +1628,11 @@
         "description": "Переглянути доступні комбінації клавіш",
         "button": "Перегляд ярликів"
       },
+      "refresh_cache": {
+        "label": "Refresh cached data",
+        "description": "Reload contacts, calendars, and folders from the server. Keeps your accounts and sessions \u2014 fixes a stale or wrong view without signing out.",
+        "button": "Refresh"
+      },
       "reset_settings": {
         "label": "Скинути налаштування",
         "description": "Відновити всі налаштування до значень за замовчуванням",

locales/zh/common.json

@@ -1628,6 +1628,11 @@
         "description": "查看可用快捷键",
         "button": "查看快捷方式"
       },
+      "refresh_cache": {
+        "label": "Refresh cached data",
+        "description": "Reload contacts, calendars, and folders from the server. Keeps your accounts and sessions \u2014 fixes a stale or wrong view without signing out.",
+        "button": "Refresh"
+      },
       "reset_settings": {
         "label": "重置设置",
         "description": "将所有设置恢复为默认值",