StatResolverTests: UnequipReturnsTheResolversRetainedSetToBaseline and
ConsumableExpiryReturnsTheResolversRetainedSetToBaseline drive 20 equip/
evaluate/unequip and activate/evaluate/expire cycles and assert the
resolver's own entry counts return to baseline, pinning Gate 1 at the
retained-set level rather than only via one WeakReference.
ARefitTargetReattachesTheModifierAfterReactivation drives the exact refit
scenario Gate 2 fixes and asserts the replacement target ends up boosted.
tests/mutation_tests_stats_power_cut2.py: one mutation per Forget() call site
(each expected red under deletion of that call), one for Gate 2's detach line,
and the StatOwner mutant swapped for Entity to match its removal.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>