First live pick after #893 chose claude-sonnet-4-5 at 0.23 over
claude-sonnet-4-6: same-family models split the probability for a
mid-weight task, and "prefer newer" is a policy, not a judgment. New
scripts/ci/choose-model.sh applies it to the distribution: among
candidates within CHOOSE_MODEL_MARGIN (0.7) of the best probability the
most recently released wins; a clear best stays; NONE yields nothing.
The picker logs the top probabilities. Four policy tests added.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
