- Relay envelope now carries source (api|csv), stations_count, and
data_updated (freshest price_last_updated the GOV.UK server reports,
independent of relay sync time).
- App decodes the new envelope metadata (RelayMeta), persists it after
each full fetch, and shows it in Settings → About → Data source:
Connection (API/CSV), Stations count, Data updated (local-formatted).
- Older relays without the fields decode cleanly (nil meta → em-dash).
- 2 new tests for meta decode + absent-meta tolerance; 37/37 pass.
The API relay (fuelboard-relay-api, official Fuel Finder source) passed
contract verification and live health (source=api, 8010 stations).
Switching the app's single relay URL to :8789; original CSV relay stays
running on :8788 if we need to roll back.