Load supply chain from PDL and display it on world map

[Sponn]

Depending on the supply chain defined in the PDL file, the supply chain should be displayed on the world map / globe.

[Hackatro]

topology is PDL-derived via #33/#38, and the exporter already emits lat/lng placements from PDL or roster entities.
But only the 4 roster-declared entities carry coordinates. The 12 PDL entities have only location (country), so they fall back to the hardcoded GAZETTEER, and an entity not in that table is dropped from the map.

Remaining scope: declare coordinates for every entity (PDL fields or a roster placements: section, to be decided).
#36 (sea routes only) was closed separately.