feat(apple): cover the window while the core boots

The core initializes asynchronously at launch, so for a moment the transfer lists
look empty and the app feels stalled. Show a full-window overlay (centered spinner
+ "Starting…") as the top layer of the root stack while coreState.isInitialized is
false; it fades out once the core is ready.

shared/src/commonMain/composeResources/values-de/strings.xml

@@ -22,6 +22,7 @@
     <string name="about_privacy_title">Datenschutz &amp; Sicherheit</string>
     <string name="about_tagline">Senden Sie Dateien direkt. Behalten Sie die Kontrolle darüber, wer sie empfängt.</string>
     <string name="about_title">Über</string>
+    <string name="app_starting">Wird gestartet…</string>
     <string name="appearance_auto_description">Der hellen oder dunklen Darstellung dieses Geräts folgen.</string>
     <string name="appearance_dark_mode">Dunkelmodus</string>
     <string name="appearance_light_mode">Hellmodus</string>

shared/src/commonMain/composeResources/values-es/strings.xml

@@ -22,6 +22,7 @@
     <string name="about_privacy_title">Privacidad y seguridad</string>
     <string name="about_tagline">Envíe archivos directamente. Mantenga el control de quién los recibe.</string>
     <string name="about_title">Acerca de</string>
+    <string name="app_starting">Iniciando…</string>
     <string name="appearance_auto_description">Seguir la apariencia clara u oscura de este dispositivo.</string>
     <string name="appearance_dark_mode">Modo oscuro</string>
     <string name="appearance_light_mode">Modo claro</string>

shared/src/commonMain/composeResources/values-fr/strings.xml

@@ -22,6 +22,7 @@
     <string name="about_privacy_title">Confidentialité et sécurité</string>
     <string name="about_tagline">Envoyez des fichiers directement. Gardez le contrôle de qui les reçoit.</string>
     <string name="about_title">À propos</string>
+    <string name="app_starting">Démarrage…</string>
     <string name="appearance_auto_description">Suivre l’apparence claire ou sombre de cet appareil.</string>
     <string name="appearance_dark_mode">Mode sombre</string>
     <string name="appearance_light_mode">Mode clair</string>

shared/src/commonMain/composeResources/values-it/strings.xml

@@ -22,6 +22,7 @@
     <string name="about_privacy_title">Privacy e sicurezza</string>
     <string name="about_tagline">Invii file direttamente. Mantenga il controllo su chi li riceve.</string>
     <string name="about_title">Informazioni</string>
+    <string name="app_starting">Avvio…</string>
     <string name="appearance_auto_description">Segue l’aspetto chiaro o scuro di questo dispositivo.</string>
     <string name="appearance_dark_mode">Modalità scura</string>
     <string name="appearance_light_mode">Modalità chiara</string>

shared/src/commonMain/composeResources/values-nl/strings.xml

@@ -22,6 +22,7 @@
     <string name="about_privacy_title">Privacy en beveiliging</string>
     <string name="about_tagline">Verstuur bestanden rechtstreeks. Houd controle over wie ze ontvangt.</string>
     <string name="about_title">Over</string>
+    <string name="app_starting">Bezig met starten…</string>
     <string name="appearance_auto_description">De lichte of donkere weergave van dit apparaat volgen.</string>
     <string name="appearance_dark_mode">Donkere modus</string>
     <string name="appearance_light_mode">Lichte modus</string>

shared/src/commonMain/composeResources/values-pl/strings.xml

@@ -22,6 +22,7 @@
     <string name="about_privacy_title">Prywatność i bezpieczeństwo</string>
     <string name="about_tagline">Wysyłaj pliki bezpośrednio. Zachowaj kontrolę nad tym, kto je otrzymuje.</string>
     <string name="about_title">Informacje</string>
+    <string name="app_starting">Uruchamianie…</string>
     <string name="appearance_auto_description">Dopasuj do jasnego lub ciemnego wyglądu tego urządzenia.</string>
     <string name="appearance_dark_mode">Tryb ciemny</string>
     <string name="appearance_light_mode">Tryb jasny</string>

shared/src/commonMain/composeResources/values-pt/strings.xml

@@ -22,6 +22,7 @@
     <string name="about_privacy_title">Privacidade e segurança</string>
     <string name="about_tagline">Envie ficheiros diretamente. Mantenha o controlo sobre quem os recebe.</string>
     <string name="about_title">Acerca de</string>
+    <string name="app_starting">A iniciar…</string>
     <string name="appearance_auto_description">Acompanhar o aspeto claro ou escuro deste dispositivo.</string>
     <string name="appearance_dark_mode">Modo escuro</string>
     <string name="appearance_light_mode">Modo claro</string>

shared/src/commonMain/composeResources/values-ru/strings.xml

@@ -22,6 +22,7 @@
     <string name="about_privacy_title">Конфиденциальность и безопасность</string>
     <string name="about_tagline">Отправляйте файлы напрямую. Сохраняйте контроль над тем, кто их получает.</string>
     <string name="about_title">О приложении</string>
+    <string name="app_starting">Запуск…</string>
     <string name="appearance_auto_description">Следовать светлому или тёмному оформлению этого устройства.</string>
     <string name="appearance_dark_mode">Тёмный режим</string>
     <string name="appearance_light_mode">Светлый режим</string>

shared/src/commonMain/composeResources/values/strings.xml

@@ -22,6 +22,7 @@
     <string name="about_privacy_title">Privacy &amp; security</string>
     <string name="about_tagline">Send files directly. Stay in control of who receives them.</string>
     <string name="about_title">About</string>
+    <string name="app_starting">Starting…</string>
     <string name="appearance_auto_description">Match this device’s light or dark appearance.</string>
     <string name="appearance_dark_mode">Dark mode</string>
     <string name="appearance_light_mode">Light mode</string>