Add RasterLayer, TileServer-based HeatmapOverlay across providers

[wf9a5m75]

• Add RasterLayer component
• Add local TileServer module and UrlTemplate flow for in-app tile rendering
• Implement HeatmapOverlay/HeatmapPointState with shared tile-based renderer
• Normalize zoom via MapCameraPosition and align heatmap color logic with Google Maps
• Wire HeatmapOverlay for Google Maps / Mapbox / MapLibre / HERE / ArcGIS
• Include RasterLayer integration and cache-busting versioning support

RasterLayer example

val rasterLayerState = remember {
    val source = RasterSource.UrlTemplate(
        template = "https://tile.thunderforest.com/landscape/{z}/{x}/{y}.png",
        tileSize = 512,
    )
    RasterLayerState(
        source = source,
    )
}

MapLibreMapView(
    state = mapViewState,
    modifier = modifier,
) {
    RasterLayer(rasterLayerState)
}

Heatmap example

val points =
    remember {
        TokyoPostOffices.mapIndexed { index, postOffice ->
            HeatmapPointState(
                id = "postoffice-$index",
                position = postOffice.position,
                weight = 1.0,
            )
        }
    }

MapLibreMapView(
    state = mapViewState,
    modifier = modifier,
) {
    HeatmapOverlay {
        points.forEach { pointState ->
            HeatmapPoint(pointState)
        }
    }
}

heatmap-example.webm