Adds the NASA Earth Observatory Natural Event Tracker (EONET v3) adapter,
publishing on the existing CENTRAL_DISASTER stream under
central.disaster.eonet.<category>.global subjects.
- One Central event per EONET event id; geo = most-recent geometry point.
- Composite dedup key (eonet:<id>:<latest_geometry_date_iso>) — timeline
advance re-publishes, idle re-poll suppresses.
- category_allowlist defaults to all 13 upstream categories; operator opts
OUT per-category if GDACS overlap (wildfires/floods/severeStorms/volcanoes)
produces unwanted dupes on gdacs.* subjects.
- camelCase upstream IDs (seaLakeIce, dustHaze, etc.) mapped to
lower_snake_case subject components by a single _subject_category helper.
- Country resolves to literal 'global' (no reverse-geocode in v1).
- Fall-off: missing-from-feed event emits central.disaster.eonet.<cat>.removed.global,
subtype before 'removed' per §8 canonical pattern.
Adapter ships disabled; operator enables via GUI.
