feat: set AppUserModelId for the launcher

src/XIVLauncher/App.xaml.cs

@@ -23,6 +23,7 @@
 using XIVLauncher.Settings;
 using XIVLauncher.Settings.Parsers;
 using XIVLauncher.Support;
+using XIVLauncher.Utilities;
 using XIVLauncher.Windows;
 using XIVLauncher.Xaml;
 
@@ -298,6 +299,9 @@ private void App_OnStartup(object sender, StartupEventArgs e)
                 // ignored
             }
 
+            // needs to be set early, and needs to be the same as what Squirrel sets for sanity's sake.
+            NativeFunctions.SetCurrentProcessExplicitAppUserModelID("com.squirrel.XIVLauncher.XIVLauncher");
+
             try
             {
                 LogInit.Setup(

src/XIVLauncher/Utilities/NativeFunctions.cs

@@ -0,0 +1,9 @@
+using System.Runtime.InteropServices;
+
+namespace XIVLauncher.Utilities;
+
+internal class NativeFunctions
+{
+    [DllImport("shell32.dll", SetLastError = true)]
+    internal static extern void SetCurrentProcessExplicitAppUserModelID([MarshalAs(UnmanagedType.LPWStr)] string appId);
+}