Rates Engine v0.5.0-rc.24

[v0.5.0-rc.24] — 2026-05-07

Added

• circulating_supply + market_cap_usd on /v1/currencies
  (#973). Joined from a curated quarterly-refreshed CSV at
  internal/sources/forex/circulation_data.csv covering ~25
  currencies (>95% of global fx spot volume per BIS 2022).
  Each row cites a central-bank series identifier (FRED:M2SL,
  ECB:BSI.M2, BoJ:Money_Stock_M2, ...) so the operator can
  refresh from primary documents in <5 min. Currencies absent
  from the table emit null on both fields; the frontend renders
  "—". Broader coverage via the World Bank API
  (FM.LBL.BMNY.CN, ~250 countries) is a follow-up.
• Same fields on /v1/currencies/{ticker} detail.

(rc.23 was cancelled mid-build to bundle #973 into the next
deployable tag; rc.24 supersedes it. Contents of rc.23 below
roll forward verbatim.)

Carried forward from cancelled rc.23