fix: Revert to Core API segment evaluation

[khvn26]

This reverts commit 322eb08.

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Changes

This reverts changes introduced in #2865 to eliminate an N+1 problem it supposedly adds.

How did you test this code?

Unit tests cover it.

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[codecov-commenter]

Codecov Report

Attention: 53 lines in your changes are missing coverage. Please review.

Comparison is base (1592919) 95.88% compared to head (915653b) 95.73%.
Report is 2 commits behind head on main.

Files	Patch %	Lines
api/segments/models.py	66.24%	53 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3036      +/-   ##
==========================================
- Coverage   95.88%   95.73%   -0.15%     
==========================================
  Files        1044     1046       +2     
  Lines       30663    30859     +196     
==========================================
+ Hits        29401    29544     +143     
- Misses       1262     1315      +53     

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