Add ITU Zone Overlay Rendering on Map

[w2naf]

Description

The CQ zone overlay is rendered on the map, but the ITU zone overlay is not yet implemented despite GeoJSON data being available. Add ITU zone boundary rendering to the map view.

Requirements Reference

• FR-MAP-09: ITU zone boundary overlay

Acceptance Criteria

• ITU zone boundaries rendered on the map
• Zone labels visible
• Overlay can be toggled on/off (layer control)
• Does not significantly impact map rendering performance
• GeoJSON loaded from local files (offline-first)

Blocked By

• Install, Test, and Debug Current DXDashboard on W3USR System #31 (Install, Test, and Debug Current DXDashboard)

Milestone

Milestone 1: Minimal Working System (Feb 28)