mechanics_verdict (PASS iff every post-rebalance position tracks its
effective target within tolerance + no error/gap rows; else FAIL naming
offending symbols) and indicative_slippage (per-tier mean slippage-vs-
assumed excluding low_confidence fills, reporting coverage). Frozen DTOs
PositionRow / SlippageFill / Verdict. Pure (design §5).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
