Airport administration and faster detail maps

Adds Airports as a first-class administration card and country-style detail dialog with dedicated synchronize and delete actions.
Removes Belgium, Czechia, Finland and Italy when they only exist as unused planned sources; France remains planned for the October source review.
Separates the Geozones and Airports map controls so they no longer overlap.
Reworks country maps to load a lightweight source extent first and detailed zones only for the visible viewport.
Simplifies map-only polygon geometry according to the current zoom while retaining exact imported geometry for Risk Assessment checks.
Adds dedicated bounding-box indexes and replaces per-airport correlated source checks with one current-country filter.

Changelog