Update to V1.2

1.Added new optional characters.
2.Added character selection saving function, which automatically selects the last used character.
3.Various weapon performance and user experience slightly adjusted.
4.Player stamina limit slightly increased.
5.Increased interval rest time between rounds, and random weapon crates can be quickly opened.
6.Bloodstain texture bug fixed, now visible to all players globally.
7.Victory sound effect overlapping playback bug fixed.