feat: ios in-app purchase methods (#1652)

* Add in-app purchase methods

* fix: init StoreKit controller on startup

* fix: Add transaction details to StoreKit callbacks

* nullpointer access fixed

* feat: in app purchase for ios

* feat: add IAP product fetching and logging for iOS platform

* feat: iOS Simulator building pipeline made

* feat: add support for multiple IAP product IDs and attempt purchase of the first valid one

* feat: add support for retrieving Base64-encoded app receipt after successful IAP purchase

* refactor: inapp-purchase code cleanup

* feat: iap processing

* refactor: move to storekit 2

* feat: add request to billing

* chore: add ios ifdef

* feat: remove iOS simulator specific code and exclusions

* refactor: remove unused StoreKit 2 transaction observer and simplify IAP product fetching logic

* feat: implement StoreKit 2 for iOS and macOS, add restore purchases functionality

* fix: Restore Purchases button appearance updated

* feat: enhance error handling and duplicate config detection in ApiConfigsController

* feat: add support for Mac OS NE in-app purchases and StoreKitController

* ci-cd fix

* Revert "ci-cd fix"

This reverts commit f22fd7a13b.

---------

Co-authored-by: vladimir.kuznetsov <nethiuswork@gmail.com>
Co-authored-by: vkamn <vk@amnezia.org>
Co-authored-by: spectrum <yyy@amnezia.org>

client/ui/models/servers_model.cpp

@@ -26,6 +26,15 @@ namespace
         constexpr char publicKeyInfo[] = "public_key";
         constexpr char expiresAt[] = "expires_at";
     }
+
+    QString normalizeVpnKey(const QString &vpnKey)
+    {
+        QString normalized = vpnKey.trimmed();
+        if (normalized.startsWith(QStringLiteral("vpn://"), Qt::CaseInsensitive)) {
+            normalized = normalized.mid(QStringLiteral("vpn://").size());
+        }
+        return normalized;
+    }
 }
 
 ServersModel::ServersModel(std::shared_ptr<Settings> settings, QObject *parent) : m_settings(settings), QAbstractListModel(parent)
@@ -718,6 +727,23 @@ bool ServersModel::isServerFromApiAlreadyExists(const QString &userCountryCode,
     return false;
 }
 
+bool ServersModel::hasServerWithVpnKey(const QString &vpnKey) const
+{
+    const QString normalizedInput = normalizeVpnKey(vpnKey);
+    if (normalizedInput.isEmpty()) {
+        return false;
+    }
+
+    for (const auto &server : std::as_const(m_servers)) {
+        const auto apiConfig = server.toObject().value(configKey::apiConfig).toObject();
+        const QString existingKey = normalizeVpnKey(apiConfig.value(apiDefs::key::vpnKey).toString());
+        if (!existingKey.isEmpty() && existingKey == normalizedInput) {
+            return true;
+        }
+    }
+    return false;
+}
+
 bool ServersModel::serverHasInstalledContainers(const int serverIndex) const
 {
     QJsonObject server = m_servers.at(serverIndex).toObject();