add initial application structure with configuration, logging, and health check endpoints

internal/controller/hero_controller.go

@@ -43,7 +43,7 @@ func (h *HeroController) GetByID(c echo.Context) error {
 	hero, err := h.svc.GetByID(c.Request().Context(), id)
 	if err != nil {
 		if err == sql.ErrNoRows {
-			return echo.NewHTTPError(http.StatusNotFound, "hero not found")
+			return c.JSON(http.StatusOK, vo.OK(nil))
 		}
 		return err
 	}