Feat: Allow Launching from launchers

Minecraft.Client/Windows64/Windows64_Minecraft.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include <string>
+
+class Windows64Minecraft {
+public:
+    static bool IsOfflineMode();
+    static std::string GetAuthenticationTicket();
+    static bool IsExternalLauncher();
+
+    struct Win64LaunchOptions
+    {
+        int screenMode;
+        bool fullscreen;
+        bool username;
+        bool token;
+    };
+};