Rates Engine v0.5.0-rc.13

[v0.5.0-rc.13] — 2026-05-06

Fixed

• /v1/coins/{slug}.price_usd applies the USDC stablecoin
  proxy. rc.12 fixed the listing query but missed the
  single-asset SQL because GetCoinBySlug's xlm_usd CTE had
  different formatting; /v1/coins/USDC returned price_usd:
  null even though /v1/coins?limit=5 returned $1.00. Same
  stablecoin-proxy now in both paths.

Changed

• Wire price_usd rounded to 10 dp. Postgres NUMERIC ×
  NUMERIC preserves 36+ digits which is pure noise on a
  display value. ROUND(..., 10) covers sub-millicent
  precision; trims the JSON payload.