Made sure apportionment works with non-consecutive list/candidate numbers

[Lionqueen94]

Resolves #2785

[codecov]

Codecov Report

❌ Patch coverage is 97.11538% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.64%. Comparing base (af935ce) to head (aee734e).

Files with missing lines	Patch %	Lines
backend/apportionment/src/structs.rs	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2807      +/-   ##
==========================================
+ Coverage   91.61%   91.64%   +0.03%     
==========================================
  Files         389      389              
  Lines       18716    18809      +93     
  Branches     2048     2048              
==========================================
+ Hits        17147    17238      +91     
- Misses       1467     1469       +2     
  Partials      102      102              

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[github-actions]

Sigrid maintainability feedback

⚠️ Your code did not improve towards your objective of 3.5 stars.

Show details

Sigrid compared your code against the baseline of 2026-02-06.

👍 What went well?

You fixed or improved 1 refactoring candidates.

Risk	System property	Location
🔴	Duplication (Fixed)	backend/apportionment/src/seat_assignment/mod.rs line 132-137 backend/apportionment/src/seat_assignment/residual_seat_assignment.rs line 125-130

👎 What could be better?

Unfortunately, 2 refactoring candidates were introduced or got worse.

Risk	System property	Location
🔴	Duplication (Introduced)	backend/apportionment/src/seat_assignment/mod.rs line 134-139 backend/apportionment/src/seat_assignment/residual_seat_assignment.rs line 125-130
🟡	Module Coupling (Introduced)	backend/apportionment/src/structs.rs

📚 Remaining technical debt

9 refactoring candidates didn't get better or worse, but are still present in the code you touched.

View this system in Sigrid to explore your technical debt

⭐️ Sigrid ratings

System property	System on 2026-02-06	Before changes	New/changed code
Volume	3.4	N/A	N/A
Duplication	3.7	5.1	5.2
Unit Size	2.2	2.2	2.2
Unit Complexity	3.3	2.9	2.9
Unit Interfacing	2.9	0.8	0.9
Module Coupling	3.4	5.5	3.3
Component Independence	2.0	N/A	N/A
Component Entanglement	2.4	N/A	N/A
Maintainability	2.9	3.6	3.0

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[github-actions]

PDF Diff Summary

Comparing against base branch: main

File	Status
model-n-10-2.pdf	✅ No changes
model-na-14-2-bijlage1.pdf	✅ No changes
model-na-14-2.pdf	✅ No changes
model-na-31-2-bijlage1.pdf	✅ No changes
model-na-31-2-inlegvel.pdf	✅ No changes
model-na-31-2.pdf	✅ No changes
model-p-2a.pdf	✅ No changes