Write ImGui config to an appropriate folder instead of the current one.

public/raid/raid.hpp

@@ -7,6 +7,7 @@
 #include <cstdint>
 #include <functional>
 #include <fmt/format.h>
+#include <mijin/virtual_filesystem/stacked.hpp>
 #include <SDL3/SDL.h>
 
 namespace raid
@@ -33,6 +34,8 @@ private:
     SDL_Window* mWindow = nullptr;
     SDL_GLContext mGLContext = nullptr;
 
+    mijin::StackedFileSystemAdapter mFS;
+
     using glClear_fn_t = void (*)(std::uint32_t);
     using glClearColor_fn_t = void (*)(float, float, float, float);
 
@@ -46,6 +49,7 @@ public:
 
 protected:
     virtual void render() = 0;
+    virtual std::string getFolderName() = 0;
     virtual void handleMessage(const Message& message);
     virtual void handleSDLEvent(const SDL_Event& event);
 
@@ -106,6 +110,8 @@ private:
     bool initImGui();
     void cleanup();
     void handleSDLEvents();
+    void loadImGuiConfig();
+    void saveImGuiConfig();
 };
 
 using render_cb_t = std::function<void()>;
@@ -115,6 +121,7 @@ struct QuickAppOptions
     {
         render_cb_t render;
     } callbacks;
+    std::string folderName = "raid";
 };
 
 class QuickApp : public Application
@@ -124,6 +131,7 @@ private:
 public:
     void init(QuickAppOptions options);
     void render() override;
+    std::string getFolderName() override;
 };
 
 [[nodiscard]]