feat: add difficulty parameter to roguelike preset

[wangl-cc]

No description provided.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 66.17%. Comparing base (3629373) to head (7d5cb6c).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #351   +/-   ##
=======================================
  Coverage   66.16%   66.17%           
=======================================
  Files          42       42           
  Lines        3626     3630    +4     
=======================================
+ Hits         2399     2402    +3     
- Misses       1227     1228    +1     

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[wangl-cc]

CC: @Alan-Charred, 不知为什么 Reviewer 不能选你，所以在只能艾特你了

[Alan-Charred]

CC: @Alan-Charred, 不知为什么 Reviewer 不能选你，所以在只能艾特你了

看了一圈没问题，感恩的心！
（rust 真好，有各种 assertion 来做 sanity check）

不能选 reviewer 可能是因为不强制要求 review，我也没搞懂这个机制Orz