Update to Version 1.31.0

- Changed "Key Config" on the title screen to "Settings".
- Added a function that allows you to set the language and volume on the title screen.
- Korean language support for the key configuration screen.
- Fixed a bug that the Steam achievement unlock notification was not displayed.
- Adjusted the line break position of the character name in the conversation column.
- Unify the capitalization rules of the English version.
- Renamed "config" in English to "settings".
- Corrected the thickness of the outline of characters in the Korean version.