Rates Engine v0.5.0-rc.20

Fixed

• /v1/coins/{slug} 500 regression on rc.18. PR #794 added
  change_1h_pct, change_24h_pct, change_7d_pct references
  to getCoinBySlugSQL but missed adding the corresponding
  xlm_usd_1h / xlm_usd_24h / xlm_usd_7d CTE definitions
  (they were added to listCoinsBaseSelect correctly).
  Postgres rejected every non-native slug lookup with
  relation "xlm_usd_1h" does not exist (42P01). Caught by
  watching r1 API logs — explorer build was hammering the API
  with ~150 errors/min on slugs like ARS, PEPE, GAZPROM, KOGAS.

Added

• Open Graph + Twitter cards for explorer + status sites.
  Both subsites now ship a 1200×630 SVG OG image plus full
  openGraph.images + twitter.images metadata so links
  shared in Slack / Twitter / LinkedIn render as proper preview
  cards instead of bare URL chips. Explorer card has the
  network-line motif + "Pricing for every asset on Stellar";
  status card has the live-pulse dot + "System status".
• Home Try-the-API panel: Run-it live + 7 examples. The
  panel now ships with 7 canonical curls (price, coin detail,
  coins listing, top markets, history, cursors, incidents) and
  a ▶ button next to the Copy button — click to fetch the same
  URL inline and render the JSON response (4 KB cap, syntax-
  pretty when JSON, raw otherwise). Closes the loop between
  "what should I try?" → "what does it actually return?" without
  the visitor leaving the page.
• /network page rebuilt around live data. Drops the
  "Coming next" placeholder and renders the same network stats
  strip as the home page (24h volume, active markets, asset
  count, sources online, XLM price), plus the live network panel
  • Top markets + Top assets tables. Architecture context now
    describes what's currently observable on R1 instead of what's
    conceptually planned for R2/R3. Footnote section honestly
    enumerates what's still TBD (TVL, peg health, fee market) so
    the page can grow without surprising the reader.
• /sources/{name} per-venue detail page on the explorer.
  Static-export route enumerating every registered source from
  /v1/sources. Renders the source's registry profile (class /
  subclass / contributes_to_vwap / default_weight / paid /
  backfill_safe) plus per-(source, sub_source) ingest cursors
  pulled from /v1/diagnostics/cursors with green/amber/red lag
  pills. Sources table rows on /sources are now clickable Links
  into the new detail page.