Rates Engine v0.5.0-rc.74

[v0.5.0-rc.74] — 2026-05-23

Fixed

• verify-archive parallelism fix crashed on least-privilege
  MinIO IAM. rc.73 added tip-resolution for -to=0 -workers N
  via datastore.FindLatestLedgerSequence, but that — and the
  per-chunk workers' BufferedStorageBackend.PrepareRange for
  BoundedRange — both require s3:ListBucket. r1's
  ratesengine_reader MinIO IAM grants GetObject only (single-
  chunk UnboundedRange doesn't need List, which is why the
  pre-rc.73 single-chunk-by-accident behaviour worked). The
  systemd nightly's -workers 12 -to=0 therefore hit AccessDenied
  on first fire of the rc.73 binary, breaking the nightly chain
  walk. Now the resolution path is fail-soft: on either
  NewDataStore or FindLatestLedgerSequence denial, log a clear
  "fall back to single-chunk serial; grant s3:ListBucket to the
  reader IAM to enable parallelism" message and demote workers=1.
  Old single-chunk behaviour is fully preserved; operators who
  grant List get the real parallel speedup automatically. Explicit
  -to N -workers M still loud-fails on per-worker AccessDenied
  (operator asked for parallelism, so the failure is actionable).