011 collided with the existing 011_add_regime_snapshots (duplicate revision id
and a second head branching off 010), which broke `alembic upgrade head`. Chain
the benchmark_prices migration after regime_snapshots so the history is linear
again (010 -> 011 regime_snapshots -> 012 benchmark_prices, single head).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
