i18n: localize all MessageBox dialogs

The previous batch only covered XAML strings. The runtime MessageBox
dialogs (errors, confirmations, info popups) stayed hardcoded in
French, breaking immersion for non-FR users.

Added ~15 keys to Strings.cs for the MessageBox bodies and titles:
- error / launch error / confirm / info / patience / language change /
  release notes (titles)
- launch failed / self-update failed / install failed / uninstall
  failed / uninstall confirm with version+folder+size / no release
  notes / fetch failed / clear cache confirm / deactivate license
  (short and detailed) / language restart (bodies)

Some are parametrized (MsgLaunchFailed(detail), MsgUninstallConfirm
(version, folder, size)) so the localized strings interpolate the
runtime values cleanly across all 5 languages.

Replaced every MessageBox.Show in MainViewModel, SettingsViewModel
and LicenseDetailsDialog.xaml.cs to use these keys. The "Échec : "
prefix in the cache-clear error was dropped — the error message alone
is sufficient with Strings.MsgBoxError as the dialog title.

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

src/PSLauncher.App/ViewModels/MainViewModel.cs

@@ -12,6 +12,7 @@ using PSLauncher.Core.Configuration;
 using PSLauncher.Core.Downloads;
 using PSLauncher.Core.Installations;
 using PSLauncher.Core.Licensing;
+using PSLauncher.Core.Localization;
 using PSLauncher.Core.Manifests;
 using PSLauncher.Core.Process;
 using PSLauncher.Core.Updates;
@@ -338,8 +339,8 @@ public sealed partial class MainViewModel : ObservableObject
         catch (Exception ex)
         {
             _logger.LogError(ex, "Self-update failed");
-            MessageBox.Show($"Mise à jour du launcher échouée :\n\n{ex.Message}",
+            MessageBox.Show(Strings.MsgSelfUpdateFailed(ex.Message),
-                "Erreur", MessageBoxButton.OK, MessageBoxImage.Error);
+                Strings.MsgBoxError, MessageBoxButton.OK, MessageBoxImage.Error);
             StatusMessage = $"Erreur self-update : {ex.Message}";
             IsBusy = false;
         }
@@ -463,15 +464,15 @@ public sealed partial class MainViewModel : ObservableObject
         catch (Exception ex)
         {
             _logger.LogError(ex, "Launch failed");
-            MessageBox.Show($"Impossible de lancer la version :\n\n{ex.Message}",
+            MessageBox.Show(Strings.MsgLaunchFailed(ex.Message),
-                "Erreur de lancement", MessageBoxButton.OK, MessageBoxImage.Error);
+                Strings.MsgBoxLaunchError, MessageBoxButton.OK, MessageBoxImage.Error);
         }
     }
 
     private async Task InstallVersionAsync(VersionRowViewModel row)
     {
         if (row.Remote is null) return;
-        if (IsBusy) { MessageBox.Show("Une autre opération est déjà en cours.", "Patience", MessageBoxButton.OK, MessageBoxImage.Information); return; }
+        if (IsBusy) { MessageBox.Show(Strings.MsgBusy, Strings.MsgBoxPatience, MessageBoxButton.OK, MessageBoxImage.Information); return; }
 
         IsBusy = true;
         _activeRow = row;
@@ -555,8 +556,8 @@ public sealed partial class MainViewModel : ObservableObject
             row.ProgressDetail = null;
             row.ProgressPercent = 0;
             MessageBox.Show(
-                $"Le téléchargement ou l'installation a échoué :\n\n{ex.Message}",
+                Strings.MsgInstallFailed(ex.Message),
-                "Erreur", MessageBoxButton.OK, MessageBoxImage.Error);
+                Strings.MsgBoxError, MessageBoxButton.OK, MessageBoxImage.Error);
             StatusMessage = $"Erreur : {ex.Message}";
             _toastService.ShowError($"Échec v{row.Version}", ex.Message);
         }
@@ -575,13 +576,13 @@ public sealed partial class MainViewModel : ObservableObject
 
         var sizeStr = FormatSize(row.SizeBytes);
         var confirm = MessageBox.Show(
-            $"Supprimer la version v{row.Version} ?\n\nDossier : {row.FolderPath}\nLibérera {sizeStr}.\n\nCette action est irréversible.",
+            Strings.MsgUninstallConfirm(row.Version, row.FolderPath, sizeStr),
-            "Confirmer la suppression",
+            Strings.MsgBoxConfirm,
             MessageBoxButton.YesNo, MessageBoxImage.Warning, MessageBoxResult.No);
 
         if (confirm != MessageBoxResult.Yes) return;
 
-        if (IsBusy) { MessageBox.Show("Une autre opération est déjà en cours.", "Patience", MessageBoxButton.OK, MessageBoxImage.Information); return; }
+        if (IsBusy) { MessageBox.Show(Strings.MsgBusy, Strings.MsgBoxPatience, MessageBoxButton.OK, MessageBoxImage.Information); return; }
 
         IsBusy = true;
         row.State = VersionRowState.Uninstalling;
@@ -596,7 +597,7 @@ public sealed partial class MainViewModel : ObservableObject
         {
             _logger.LogError(ex, "Uninstall failed for {Version}", row.Version);
             row.State = VersionRowState.InstalledIdle;
-            MessageBox.Show($"Suppression échouée : {ex.Message}", "Erreur",
+            MessageBox.Show(Strings.MsgUninstallFailed(ex.Message), Strings.MsgBoxError,
                 MessageBoxButton.OK, MessageBoxImage.Error);
             StatusMessage = $"Erreur : {ex.Message}";
         }
@@ -611,8 +612,8 @@ public sealed partial class MainViewModel : ObservableObject
         var url = row.Remote?.ReleaseNotesUrl;
         if (string.IsNullOrEmpty(url))
         {
-            MessageBox.Show("Aucune release note disponible pour cette version.",
+            MessageBox.Show(Strings.MsgNoReleaseNotes,
-                "Release notes", MessageBoxButton.OK, MessageBoxImage.Information);
+                Strings.MsgBoxReleaseNotes, MessageBoxButton.OK, MessageBoxImage.Information);
             return;
         }
         string notes;
@@ -620,8 +621,8 @@ public sealed partial class MainViewModel : ObservableObject
         catch (Exception ex)
         {
             _logger.LogWarning(ex, "Failed to fetch release notes");
-            MessageBox.Show($"Impossible de récupérer les release notes :\n{ex.Message}",
+            MessageBox.Show(Strings.MsgReleaseNotesFetchFailed(ex.Message),
-                "Erreur", MessageBoxButton.OK, MessageBoxImage.Warning);
+                Strings.MsgBoxError, MessageBoxButton.OK, MessageBoxImage.Warning);
             return;
         }
 

src/PSLauncher.App/ViewModels/SettingsViewModel.cs

@@ -9,6 +9,7 @@ using Microsoft.Extensions.Logging;
 using PSLauncher.Core.Configuration;
 using PSLauncher.Core.Downloads;
 using PSLauncher.Core.Licensing;
+using PSLauncher.Core.Localization;
 using PSLauncher.Models;
 
 namespace PSLauncher.App.ViewModels;
@@ -185,8 +186,8 @@ public sealed partial class SettingsViewModel : ObservableObject
     private void ClearCache()
     {
         var confirm = MessageBox.Show(
-            "Vider le cache de téléchargements ? Les téléchargements en cours/pause seront perdus.",
+            Strings.MsgClearCacheConfirm,
-            "Confirmer",
+            Strings.MsgBoxConfirm,
             MessageBoxButton.YesNo, MessageBoxImage.Warning, MessageBoxResult.No);
         if (confirm != MessageBoxResult.Yes) return;
 
@@ -201,7 +202,7 @@ public sealed partial class SettingsViewModel : ObservableObject
         catch (Exception ex)
         {
             _logger.LogError(ex, "ClearCache failed");
-            MessageBox.Show("Échec : " + ex.Message, "Erreur", MessageBoxButton.OK, MessageBoxImage.Error);
+            MessageBox.Show(ex.Message, Strings.MsgBoxError, MessageBoxButton.OK, MessageBoxImage.Error);
         }
     }
 
@@ -232,8 +233,8 @@ public sealed partial class SettingsViewModel : ObservableObject
             // la nouvelle langue. Plutôt que de demander à l'utilisateur de fermer/rouvrir,
             // on spawne un cmd qui attend la fermeture puis relance.
             var ok = MessageBox.Show(
-                "Le launcher va redémarrer pour appliquer la nouvelle langue.",
+                Strings.MsgLanguageRestart,
-                "Changement de langue",
+                Strings.MsgBoxLanguageChange,
                 MessageBoxButton.OKCancel, MessageBoxImage.Information, MessageBoxResult.OK);
             if (ok == MessageBoxResult.OK)
             {
@@ -263,8 +264,8 @@ public sealed partial class SettingsViewModel : ObservableObject
     private void DeactivateLicense()
     {
         var confirm = MessageBox.Show(
-            "Désactiver la license sur cette machine ?\nTu pourras la réactiver avec ta clé.",
+            Strings.MsgDeactivateLicenseConfirm,
-            "Confirmer",
+            Strings.MsgBoxConfirm,
             MessageBoxButton.YesNo, MessageBoxImage.Question, MessageBoxResult.No);
         if (confirm != MessageBoxResult.Yes) return;
         _licenseService.Clear();

src/PSLauncher.App/Views/LicenseDetailsDialog.xaml.cs

@@ -1,6 +1,7 @@
 using System.Windows;
 using System.Windows.Media;
 using PSLauncher.Core.Licensing;
+using PSLauncher.Core.Localization;
 using PSLauncher.Models;
 
 namespace PSLauncher.App.Views;
@@ -66,10 +67,8 @@ public partial class LicenseDetailsDialog : Window
     private void OnDeactivate(object sender, RoutedEventArgs e)
     {
         var confirm = MessageBox.Show(
-            "Désactiver la license sur cette machine ?\n\n" +
+            Strings.MsgDeactivateLicenseDetailedConfirm,
-            "Tu pourras la réactiver plus tard avec ta clé. " +
+            Strings.MsgBoxConfirm,
-            "Les versions déjà installées restent utilisables.",
-            "Confirmer la désactivation",
             MessageBoxButton.YesNo, MessageBoxImage.Question, MessageBoxResult.No);
         if (confirm != MessageBoxResult.Yes) return;
         _licenseService.Clear();

src/PSLauncher.Core/Localization/Strings.cs

@@ -152,4 +152,110 @@ public static class Strings
     // ==================== UPDATE ====================
     public static string UpdateAvailableTitle => T("Mise à jour disponible", "Update available", "有可用更新", "มีการอัปเดต", "تحديث متاح");
     public static string UpdateDownload       => T("⬇  Télécharger", "⬇  Download", "⬇  下载", "⬇  ดาวน์โหลด", "⬇  تنزيل");
+
+    // ==================== MESSAGEBOX TITLES ====================
+    public static string MsgBoxError       => T("Erreur",         "Error",          "错误",         "ข้อผิดพลาด",      "خطأ");
+    public static string MsgBoxLaunchError => T("Erreur de lancement", "Launch error", "启动错误",  "เปิดใช้งานล้มเหลว", "خطأ في التشغيل");
+    public static string MsgBoxConfirm     => T("Confirmer",      "Confirm",        "确认",         "ยืนยัน",          "تأكيد");
+    public static string MsgBoxInfo        => T("Information",    "Information",    "信息",         "ข้อมูล",          "معلومة");
+    public static string MsgBoxPatience    => T("Patience",       "Please wait",    "请稍候",       "โปรดรอ",         "يرجى الانتظار");
+    public static string MsgBoxLanguageChange => T("Changement de langue", "Language change", "更改语言", "เปลี่ยนภาษา", "تغيير اللغة");
+    public static string MsgBoxReleaseNotes => T("Release notes", "Release notes",   "版本说明",     "บันทึกการเปลี่ยนแปลง", "ملاحظات الإصدار");
+
+    // ==================== MESSAGEBOX MESSAGES ====================
+    public static string MsgBusy => T(
+        "Une autre opération est déjà en cours.",
+        "Another operation is already in progress.",
+        "另一个操作正在进行中。",
+        "มีการดำเนินการอื่นอยู่แล้ว",
+        "هناك عملية أخرى قيد التنفيذ بالفعل."
+    );
+
+    public static string MsgLaunchFailed(string detail) => T(
+        $"Impossible de lancer la version :\n\n{detail}",
+        $"Could not launch the version:\n\n{detail}",
+        $"无法启动该版本：\n\n{detail}",
+        $"ไม่สามารถเปิดเวอร์ชันนี้ได้:\n\n{detail}",
+        $"تعذر تشغيل النسخة:\n\n{detail}"
+    );
+
+    public static string MsgSelfUpdateFailed(string detail) => T(
+        $"Mise à jour du launcher échouée :\n\n{detail}",
+        $"Launcher update failed:\n\n{detail}",
+        $"启动器更新失败：\n\n{detail}",
+        $"การอัปเดต Launcher ล้มเหลว:\n\n{detail}",
+        $"فشل تحديث المُشغِّل:\n\n{detail}"
+    );
+
+    public static string MsgInstallFailed(string detail) => T(
+        $"Le téléchargement ou l'installation a échoué :\n\n{detail}",
+        $"Download or installation failed:\n\n{detail}",
+        $"下载或安装失败：\n\n{detail}",
+        $"การดาวน์โหลดหรือติดตั้งล้มเหลว:\n\n{detail}",
+        $"فشل التنزيل أو التثبيت:\n\n{detail}"
+    );
+
+    public static string MsgUninstallFailed(string detail) => T(
+        $"Suppression échouée : {detail}",
+        $"Uninstall failed: {detail}",
+        $"卸载失败：{detail}",
+        $"การถอนการติดตั้งล้มเหลว: {detail}",
+        $"فشل الإزالة: {detail}"
+    );
+
+    public static string MsgUninstallConfirm(string version, string folder, string size) => T(
+        $"Supprimer la version v{version} ?\n\nDossier : {folder}\nLibérera {size}.\n\nCette action est irréversible.",
+        $"Uninstall version v{version}?\n\nFolder: {folder}\nWill free {size}.\n\nThis action is irreversible.",
+        $"卸载版本 v{version}？\n\n文件夹：{folder}\n将释放 {size}。\n\n此操作不可逆。",
+        $"ถอนการติดตั้งเวอร์ชัน v{version}?\n\nโฟลเดอร์: {folder}\nจะคืนพื้นที่ {size}\n\nการกระทำนี้ไม่สามารถย้อนกลับได้",
+        $"إلغاء تثبيت النسخة v{version}؟\n\nالمجلد: {folder}\nسيتم تحرير {size}.\n\nهذا الإجراء لا رجعة فيه."
+    );
+
+    public static string MsgNoReleaseNotes => T(
+        "Aucune release note disponible pour cette version.",
+        "No release notes available for this version.",
+        "此版本没有可用的版本说明。",
+        "ไม่มีบันทึกการเปลี่ยนแปลงสำหรับเวอร์ชันนี้",
+        "لا توجد ملاحظات إصدار متاحة لهذه النسخة."
+    );
+
+    public static string MsgReleaseNotesFetchFailed(string detail) => T(
+        $"Impossible de récupérer les release notes :\n{detail}",
+        $"Could not fetch release notes:\n{detail}",
+        $"无法获取版本说明：\n{detail}",
+        $"ไม่สามารถดึงบันทึกการเปลี่ยนแปลงได้:\n{detail}",
+        $"تعذر جلب ملاحظات الإصدار:\n{detail}"
+    );
+
+    public static string MsgClearCacheConfirm => T(
+        "Vider le cache de téléchargements ? Les téléchargements en cours/pause seront perdus.",
+        "Clear the download cache? In-progress / paused downloads will be lost.",
+        "清空下载缓存？正在进行或暂停的下载将丢失。",
+        "ล้างแคชดาวน์โหลด? การดาวน์โหลดที่กำลังดำเนินการ/หยุดชั่วคราวจะสูญหาย",
+        "مسح ذاكرة التخزين المؤقت للتنزيلات؟ ستفقد التنزيلات قيد التقدم أو الموقوفة مؤقتًا."
+    );
+
+    public static string MsgDeactivateLicenseConfirm => T(
+        "Désactiver la license sur cette machine ?\nTu pourras la réactiver avec ta clé.",
+        "Deactivate the license on this machine?\nYou can reactivate it later with your key.",
+        "在此机器上停用许可证？\n您可以稍后用密钥重新激活。",
+        "ปิดใช้งานใบอนุญาตบนเครื่องนี้?\nคุณสามารถเปิดใช้งานใหม่ในภายหลังด้วยคีย์ของคุณ",
+        "إلغاء تنشيط الترخيص على هذا الجهاز؟\nيمكنك إعادة تنشيطه لاحقًا بمفتاحك."
+    );
+
+    public static string MsgDeactivateLicenseDetailedConfirm => T(
+        "Désactiver la license sur cette machine ?\n\nTu pourras la réactiver plus tard avec ta clé. Les versions déjà installées restent utilisables.",
+        "Deactivate the license on this machine?\n\nYou can reactivate it later with your key. Already-installed versions remain usable.",
+        "在此机器上停用许可证？\n\n您可以稍后用密钥重新激活。已安装的版本仍可使用。",
+        "ปิดใช้งานใบอนุญาตบนเครื่องนี้?\n\nคุณสามารถเปิดใช้งานใหม่ในภายหลังด้วยคีย์ของคุณ เวอร์ชันที่ติดตั้งแล้วยังคงใช้งานได้",
+        "إلغاء تنشيط الترخيص على هذا الجهاز؟\n\nيمكنك إعادة تنشيطه لاحقًا بمفتاحك. تظل النسخ المثبتة قابلة للاستخدام."
+    );
+
+    public static string MsgLanguageRestart => T(
+        "Le launcher va redémarrer pour appliquer la nouvelle langue.",
+        "The launcher will restart to apply the new language.",
+        "启动器将重启以应用新语言。",
+        "Launcher จะรีสตาร์ทเพื่อใช้ภาษาใหม่",
+        "سيتم إعادة تشغيل المُشغِّل لتطبيق اللغة الجديدة."
+    );
 }