v0.1.10: aggregate roll-up classification + flag legend

aggregate roll-up classification + flag legend

Fixes sub-5000 roll-up areas defeating aggregate exclusion and widens
the data-quality flag legend to the full FAOSTAT set.

Changed:

• Data-quality flag legend widened from a closed A/E/I list to the
  full FAOSTAT set (A/B/E/I/M/T/X, plus others per domain), reframed
  as an open set — server instructions, faostat_query_observations,
  faostat_dataframe_query, faostat_commodity_profile (#6)

Fixed:

• faostat_resolve_codes and faostat_query_observations now agree
  on sub-5000 roll-up areas (China=351, 265) via a shared
  isAggregateAreaCode() predicate — no more double-counting a region
  against its member countries in a naive SUM (#4)

99 tests pass; bun run devcheck clean.

CHANGELOG v0.1.10