Weber vote-for-or-against-k: IC-coupled ballots (default) + optional uniform types

[endolith]

Summary

Rebased onto master (resolves conflicts from strategies package flatten in #47).

Adds Weber vote-for-or-against-k simulation support:

• vote_for_or_against_k in elsim/strategies.py — each voter flips a fair coin, then either +1 on their top-k candidates by utility or -1 on their bottom-k (IC-coupled ballots; ties broken with jitter).
• best_vote_for_or_against_k(m) — discrete search replacing round(alpha * m); fixes cases like m=91 → k=34.
• Effectiveness table example — Monte Carlo SUE for best vote-for-or-against-k via combined_approval.
• Benchmark script (examples/weber_voa_k_ballot_variants_benchmark.py) — compares repo strategy vs simultaneous ±, same-top XOR, uniform subset, and vote-for-k baseline against Weber's closed form.

Uniform-type ballots are demonstrated in the benchmark script (ballot_uniform_subset_coin); the exported API is the utility-ranked coin strategy only.

Verification

pip install -e ".[test,examples]"
ruff check . --select=E9,F63,F7,F82
pytest

All 221 tests pass.

  

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.49%. Comparing base (14b8d55) to head (a969ece).

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #57      +/-   ##
==========================================
+ Coverage   96.37%   96.49%   +0.12%     
==========================================
  Files          17       17              
  Lines         496      514      +18     
==========================================
+ Hits          478      496      +18     
  Misses         18       18              

Flag	Coverage Δ
no-numba	95.91% <100.00%> (+0.14%)	⬆️
numba	88.52% <100.00%> (+0.41%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.