R2-First Write-Ahead Log

Status: stub. Day 4 deliverable.

Blueprint v4.0 §7.1 — every write that might land in D1 (the audit log of record) is committed to R2 first as a Write-Ahead Log entry. Only after R2 acknowledges the bytes does the D1 transaction proceed.

If D1 ever falls behind R2 (e.g. crash mid-batch, DO restart), the Reconciliation Worker walks the R2 prefix and drains pending entries into D1. The audit log can never be ahead of the WAL — only behind, transiently. Recovery is bounded and provable.