I Became the Founding Empress in Ancient Times with a System

Strong female lead + fictional setting + farming + stockpiling supplies + infrastructure + claiming kingship in a chaotic age (Contains many original worldbuilding details.) [The male lead is mostly in the background. I'm not very good at writing romance, so this story focuses almost entirely on the female lead's career.] Transmigrated as a county magistrate, she faces starving people in front of her and Japanese pirates lurking behind. With a dilapidated county office, an emperor who exploits the people, and an ineffectual superior, Sheng Chang'an can only build her own empire in this absurd world, drive out foreign enemies, and bring peace to the land. Build high walls, stockpile grain, and claim the throne slowly. First, she'll start with this county...