Map export: PNG, JPEG, PDF formats. Title, DPI, JPEG quality. Legend column layout.
Test plan: 15-export.md
Navigator config (for large legend export): demos/20-export-map-large-legend.json
Export button in app bar. Click to open the export modal. Test PNG, JPEG (quality slider), PDF formats and DPI options.
Many layers with large legend entries. Tests legend column layout and pagination in exported image/PDF.
Layers with missing or broken legend entries. Verifies export handles edge cases without crashing.