show recipes visually instead of describing them in text

src/lib/config/RecipesConfig.h

@@ -32,10 +32,6 @@ struct RecipeDef
     std::vector<RecipeIngredient> inputs;
     std::vector<RecipeOutput> outputs;
     double durationSeconds;
-    // Optional id of the item whose icon represents this recipe in the recipe-
-    // selection dialog (REQ-UI-RECIPE-ICON). When unset, the first output item is
-    // used. A missing icon file for that item is not an error (REQ-UI-ITEM-ICON).
-    std::optional<std::string> icon;
     // Assembler only. When true, this recipe is available from game start
     // regardless of the implicit item graph — used for base recipes that no
     // schematic's materials reach (e.g. building blocks). See REQ-LOCK-IMPLICIT.