Sprint 223 Plan: Parity Metrics and Reporting Closure

Goal

Make parity-block behavior visible in matrix summary so unresolved divergence and blocked parity are separable.

Step 2154: Add ab_consistency_blocked_count aggregate metric.
Step 2155: Keep unresolved divergence metric (ab_prod_divergence_count) as hard signal.
Step 2156: Re-run hard suites and confirm divergence target is zero.
Step 2157: Document partial-vs-closed interpretation in tracker docs.
Step 2158: Add Sprint223IntegrationSummary.h.