Open auth in browser fallback for Linux

shared/src/jvmMain/kotlin/net/keinekekse/app/auth/AuthModule.jvm.kt

@@ -13,7 +13,7 @@ actual fun openInBrowser(url: Url) {
     }
     val desktop = Desktop.getDesktop()
     if (!desktop.isSupported(Desktop.Action.BROWSE)) {
-        // TODO check if Linux -> run xdg-open $url
+        // fallback for Linux (tested only on Debian 13)
         if (System.getProperty("os.name").lowercase(Locale.getDefault()).contains("linux")) {
             // throws at error - that's all that matters here
             ExecutionResult(listOf("xdg-open", url.toString()))