feat: Debug view for MultiCOGLayer

[kylebarron]

For #142, related to #147

Change list

• Introduce UvTransform named tuple type (readonly [offsetX, offsetY, scaleX, scaleY]) as a shared type in deck.gl-raster
  • This replaces the bare [number, number, number, number] type, which makes it hard to know what each item is doing.
• Add debug, debugOpacity, and debugLevel props to MultiCOGLayer
• Preserve secondary tile CRS corners and metadata during fetch when debug: true
• Render color-coded tile boundary outlines per tileset (red for primary, cyan/yellow/magenta/lime for secondaries) using PathLayer
• Render tiered text labels at tile centers using TextLayer, with 3 verbosity levels:
  • Level 1: tile index + resolution
  • Level 2: + UV transform + tile count
  • Level 3: + stitched dimensions + meters/pixel
• Forward debug/debugOpacity to RasterLayer for reprojection mesh overlay
• Add debug toggle checkbox, detail level selector, and opacity slider to Sentinel-2 example app

Future work

• UV transform sub-region visualizer
• Interactive toggling of individual tileset overlays