feat(framework): inicializar contexto ImPlot3D en app_base

ImPlot3D::CreateContext() / DestroyContext() acoplado al ciclo de
vida de ImPlot. Cualquier app que use fn::run_app obtiene el contexto
3D listo sin codigo extra.

Issue 0028.

cpp/framework/app_base.cpp

@@ -4,6 +4,7 @@
 #include "imgui_impl_glfw.h"
 #include "imgui_impl_opengl3.h"
 #include "implot.h"
+#include "implot3d.h"
 #include "core/tokens.h"
 #include "core/icon_font.h"
 #include "core/app_settings.h"
@@ -51,6 +52,7 @@ int run_app(AppConfig config, std::function<void()> render_fn) {
     IMGUI_CHECKVERSION();
     ImGui::CreateContext();
     ImPlot::CreateContext();
+    ImPlot3D::CreateContext();
 
     ImGuiIO& io = ImGui::GetIO();
     io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;
@@ -163,6 +165,7 @@ int run_app(AppConfig config, std::function<void()> render_fn) {
     // Cleanup
     ImGui_ImplOpenGL3_Shutdown();
     ImGui_ImplGlfw_Shutdown();
+    ImPlot3D::DestroyContext();
     ImPlot::DestroyContext();
     ImGui::DestroyContext();
     glfwDestroyWindow(window);