feat: new spleeners

[midgleyc]

Also a test I wrote but forgot to add to #1905.

Chitinous Soul gives more HP the more you use so we're going to want a pref, but that can come later (e.g. after we know the cap).

[codecov]

Codecov Report

Merging #1906 (e8bf762) into main (41c2399) will increase coverage by 0.00%.
The diff coverage is n/a.

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #1906   +/-   ##
=========================================
  Coverage     36.36%   36.37%           
- Complexity    18828    18830    +2     
=========================================
  Files          1083     1083           
  Lines        166605   166605           
  Branches      35391    35391           
=========================================
+ Hits          60591    60602   +11     
+ Misses        96133    96120   -13     
- Partials       9881     9883    +2     

see 5 files with indirect coverage changes

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