fromPropertiesOnly

Rule: legend-properties-only-conversion. from's geometry branch walks every ring vertex through tileLocalXYToLngLat (boxing a Pair<Double,Double> per point) plus a full JTS-to- Mapbox polygon rebuild and CW/CCW orientation pass — real cost that scales with vertex count, not feature count. Callers that only read properties/id/sourceLayer off the result (e.g. com.xweather.mapsgl.layers.tile.VectorTileLayer.getVisibleFeatures, building legend swatches from just ADVISORY/COLOR) never touch .geometry(), so building it at all is pure waste — for a dense polygon dataset (thousands of small municipality-level shapes) this was measured to be the dominant per-refresh allocator, not the property conversion. Skips geometry entirely by reusing one shared placeholder point; never call .geometry() on the result.