FEAT: add raise-on-empty variants to true/false score aggregators

[Chen Yufeiyang (feiiiiii5)]

Description

Fixes #2883.

Aggregating an empty score list with TrueFalseScoreAggregator today returns value=False with a COMPLETE result, which is indistinguishable from a genuine "veto" verdict, and there is no way to opt into a strict check. The float-scale aggregators already solve this with raise_on_empty variants (AVERAGE_RAISE_ON_EMPTY, MAX_RAISE_ON_EMPTY, MIN_RAISE_ON_EMPTY in float_scale_score_aggregator.py); this adds the same three opt-in variants to the true/false family — AND_RAISE_ON_EMPTY, OR_RAISE_ON_EMPTY, MAJORITY_RAISE_ON_EMPTY — raising ValueError("No scores available for aggregation") on empty input. Default behavior is unchanged.

Tests and Documentation

Test: pytest tests/unit/score/test_true_false_score_aggregator.py — the 7 new tests fail on main (AttributeError: type object 'TrueFalseScoreAggregator' has no attribute 'AND_RAISE_ON_EMPTY') and pass on this branch; the existing tests, including the pinned empty-input default, are unchanged and pass. Also ran ruff format --check and ruff check (v0.16.9) on the touched files.

No JupyText notebooks affected; the float-scale *_RAISE_ON_EMPTY variants are likewise not listed in doc/code/scoring/3_combining_scorers.py.