The test_passive_update_loop test was flaky because when misfortune
randomly triggers during sim.step(), it calls StoryTeller.tell_story
which wasn't mocked, causing real LLM API calls to fail in CI.
Added StoryTeller.tell_story to the mock_llm_managers fixture.
Add splash layer, support game start, settings, exit
Modify settings layer, add "go back to splash" and "exit"
Add character threshold for history input
Closes#28
