* feat(seeds): EU country-level gas storage via GIE AGSI+
* fix(seeds): use correct GIE AGSI+ country param (country=ISO2 not country_code=)
* fix(seeds): preserve old fetchedAt on failure, raise MIN_VALID_COUNTRIES to 24
- preservePreviousSnapshot now reads the existing seed-meta and reuses
its fetchedAt instead of stamping Date.now(). A failed run that keeps
extending the snapshot no longer resets the clock, so health staleness
detection fires correctly after maxStaleMin elapses.
- health.js (both BOOTSTRAP_KEYS and STANDALONE_KEYS blocks): treat
meta.status === 'error' as immediately stale, independent of fetchedAt.
- Raise MIN_VALID_COUNTRIES from 15 to 24 (85% of 28) so a partial
upstream outage dropping several countries doesn't silently publish a
truncated dataset. Tests updated to match.
* fix(seeds): empty-string fallthrough in parseFillEntry, drop unused watch path
- parseFillEntry: switch numeric field selectors from ?? to || so that
empty-string API responses (full: "", gasInStorage: "") fall through to
the next candidate instead of producing NaN and silently dropping the
country. Date field keeps ?? since an empty string is the intended
sentinel for missing dates.
- Add two tests covering the empty-string fallthrough for fill and gwh.
- preservePreviousSnapshot: remove GAS_STORAGE_META_KEY from
extendExistingTtl — the SET that follows handles its TTL, making the
EXPIRE redundant.
- railway-set-watch-paths: drop _country-resolver.mjs from the
seed-gas-storage-countries watch list; the seed does not import it.
