Documents the 2026-04-26 split of faceset_001 (707 curated faces) into 6 substantive era buckets + 68 thin fragments, including the readiness probe evidence, the anchor-based assignment rationale (replaces transitive union-find that caused year-drift), and the re-run / apply- to-other-identity workflow. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>