ReleaseChannel: only query the OS version on updater platforms

The in-client updater only ships assets for macOS and Windows, but the
host system version was still being resolved on every platform, including
Linux where it is never used. Compute it only under the Q_OS_MACOS /
Q_OS_WIN guards.

cockatrice/src/client/network/update/client/release_channel.cpp

@@ -27,6 +27,29 @@
 
 #define GIT_SHORT_HASH_LEN 7
 
+namespace
+{
+
+#if defined(Q_OS_MACOS) || defined(Q_OS_WIN)
+// QSysInfo::productVersion() is not guaranteed to start with a number, e.g. it returns
+// "Server 2022" on Windows Server. Use the first numeric token as the major host version.
+std::optional<int> getProductVersionMajor()
+{
+    const QString versionString = QSysInfo::productVersion();
+    bool ok = false;
+    static const QRegularExpression firstNumber(R"((\d+))");
+    const auto match = firstNumber.match(versionString);
+    const int version = match.hasMatch() ? match.captured(1).toInt(&ok) : 0;
+    if (!ok) {
+        qCWarning(ReleaseChannelLog) << "Unable to determine OS version from" << versionString;
+        return std::nullopt;
+    }
+    return version;
+}
+#endif
+
+} // namespace
+
 ReleaseChannel::ReleaseChannel() : netMan(new QNetworkAccessManager(this)), response(nullptr), lastRelease(nullptr)
 {
 }
@@ -47,18 +70,21 @@ void ReleaseChannel::checkForUpdates()
 // Find assets compatible with host platform (Linux is not supported by in-client updater)
 std::optional<int> ReleaseChannel::getTargetVersionForCurrentOS(const QString &fileName)
 {
+#if defined(Q_OS_WIN) && Q_PROCESSOR_WORDSIZE == 4
+    // The published Windows assets are 64-bit only
+    Q_UNUSED(fileName);
+    return std::nullopt;
+#endif
+
     const QRegularExpression *regex = nullptr;
 
-    static const std::optional<int> systemVersion = [] {
-        bool ok = false;
-        const QString versionString = QSysInfo::productVersion();
-        const int version = versionString.split('.').first().toInt(&ok);
-        if (!ok) {
-            qCWarning(ReleaseChannelLog) << "Unable to determine OS version from" << versionString;
-            return std::optional<int>();
-        }
-        return std::optional<int>{version};
-    }();
+    // Only platforms shipping updater assets (macOS, Windows) need the host version
+    static const std::optional<int> systemVersion =
+#if defined(Q_OS_MACOS) || defined(Q_OS_WIN)
+        getProductVersionMajor();
+#else
+        std::nullopt;
+#endif
 
     if (!systemVersion) {
         return std::nullopt;