Extract image import route planning

src/app_layout.cpp

@@ -11,6 +11,7 @@
 #include "app_core/canvas_tool_ui.h"
 #include "app_core/document_layer.h"
 #include "app_core/document_canvas.h"
+#include "app_core/document_import.h"
 #include "app_core/app_status.h"
 #include "app_core/history_ui.h"
 #include "settings.h"
@@ -746,7 +747,11 @@ void App::init_menu_file()
                     pick_image([this](std::string path){
                         Image img;
                         img.load_file(path);
-                        if (img.width == img.height / 6 || img.width == img.height * 2)
+                        const auto import_plan = pp::app::plan_document_image_import(img.width, img.height);
+                        if (!import_plan)
+                            return;
+
+                        if (import_plan.value().imports_equirectangular)
                         {
                             Canvas::I->import_equirectangular(path);
                         }