[nostalgia/core] Add focusWindow, cleanup GLFW leak into Userland, change shutdown to stop main loop

src/nostalgia/core/userland/gfx_opengl.cpp

@@ -8,6 +8,9 @@
 
 #include <array>
 
+#define IMGUI_IMPL_OPENGL_ES3
+#include <imgui_impl_opengl3.h>
+
 #include <nostalgia/glutils/glutils.hpp>
 
 #include <ox/std/bit.hpp>
@@ -18,6 +21,7 @@
 
 namespace nostalgia::core {
 
+void ImGui_Impl_NewFrame() noexcept;
 
 namespace renderer {
 
@@ -267,7 +271,7 @@ void draw(Context *ctx) noexcept {
 	const auto id = ctx->rendererData<renderer::GlImplData>();
 	renderer::tickFps(id);
 	ImGui_ImplOpenGL3_NewFrame();
-	ImGui_ImplGlfw_NewFrame();
+	ImGui_Impl_NewFrame();
 	if constexpr(config::ImGuiEnabled) {
 		ImGui::NewFrame();
 	}