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.

apple/VniDrop/App/RootView.swift

@@ -63,6 +63,14 @@ struct RootView: View {
 					onRefuse: approvals.refuse
 				)
 			}
+			.overlay {
+				// A small, unobtrusive indicator while the core finishes its async
+				// startup — otherwise the lists look empty and the app feels stalled.
+				if !sendModel.coreState.isInitialized {
+					CoreStartingOverlay()
+				}
+			}
+			.animation(.easeInOut(duration: 0.25), value: sendModel.coreState.isInitialized)
 			.vniDropTheme(isDark: isDark)
 			.preferredColorScheme(appModel.themeMode.preferredColorScheme)
 			.environment(\.vniColors, isDark ? .dark : .light)
@@ -183,6 +191,32 @@ struct RootView: View {
 	}
 }
 
+/// A full-window cover with a centered spinner shown while the core is starting.
+private struct CoreStartingOverlay: View {
+	var body: some View {
+		ZStack {
+			backgroundColor.ignoresSafeArea()
+			VStack(spacing: 16) {
+				ProgressView().controlSize(.large)
+				Text(String(localized: L10n.App.starting))
+					.font(.headline)
+					.foregroundStyle(.secondary)
+			}
+		}
+		.transition(.opacity)
+		.accessibilityElement(children: .combine)
+		.accessibilityLabel(Text(String(localized: L10n.App.starting)))
+	}
+
+	private var backgroundColor: Color {
+		#if os(iOS)
+		Color(uiColor: .systemBackground)
+		#else
+		Color(nsColor: .windowBackgroundColor)
+		#endif
+	}
+}
+
 #if os(iOS)
 import UIKit
 #else

localization/strings.json

@@ -321,6 +321,20 @@
         "ru": "О приложении"
       }
     },
+    "app_starting": {
+      "context": "Shown briefly at launch while the core is still starting up.",
+      "translations": {
+        "en": "Starting…",
+        "fr": "Démarrage…",
+        "es": "Iniciando…",
+        "it": "Avvio…",
+        "de": "Wird gestartet…",
+        "pt": "A iniciar…",
+        "pl": "Uruchamianie…",
+        "nl": "Bezig met starten…",
+        "ru": "Запуск…"
+      }
+    },
     "appearance_auto_description": {
       "context": "Settings > Appearance: description for the System/auto option.",
       "translations": {

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>