MSCO 2.9.0: standalone without MSCLoader (Unity Doorstop)

- Bootstrap: Doorstop entry point, loads Harmony/Newtonsoft from the MSCO folder, hooks
  PlayMakerArrayListProxy.Awake and starts MSCO in the main menu; skips the news screen
- No MSCLoader reference anymore; key bindings in PlayerPrefs, bind console command
- Harmony 1.2 and Newtonsoft.Json in lib/ (MIT notices); build copies to <game>\MSCO
- README/CHANGELOG updated

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

JoinLinks.cs

@@ -1,6 +1,5 @@
 using System;
 using Microsoft.Win32;
-using MSCLoader;
 
 namespace MSCO
 {
@@ -31,6 +30,13 @@ namespace MSCO
                 }
                 string command = "\"" + steamExe + "\" -applaunch " + MySummerCarAppId + " " + Argument + " \"%1\"";
 
+                // Ist der MSCO Launcher installiert, gehören die Links ihm: er startet das Spiel mit MSCO (ohne MSCLoader)
+                using (RegistryKey existing = Registry.CurrentUser.OpenSubKey(@"Software\Classes\" + Scheme + @"\shell\open\command"))
+                {
+                    string current = existing != null ? existing.GetValue("") as string : null;
+                    if (current != null && current.IndexOf("MSCO-Launcher", StringComparison.OrdinalIgnoreCase) >= 0) return;
+                }
+
                 using (RegistryKey key = Registry.CurrentUser.CreateSubKey(@"Software\Classes\" + Scheme))
                 {
                     key.SetValue("", "URL:MSCO Join Link");