Nominatim's viewbox is advisory (bounded=0), so ambiguous place names like
"Pinebrook" can resolve to locations 30-40km away in the wrong town. Added
a post-geocode distance gate: results farther than geocode_max_km (default
25km) from the node are discarded with a warning log rather than written to
the incident.
Also logs distance on successful geocodes for easier audit.
New config setting: geocode_max_km (float, default 25.0)