Add deck.gl-raster as a client-side COG renderer option (deck.gl missions)

[slesaad]

Summary

Adds an optional client-side COG renderer for deck.gl-based missions, so a Cloud-Optimized GeoTIFF can be decoded and colorized in the browser on the GPU via @developmentseed/deck.gl-raster / deck.gl-geotiff — with no tile server in the loop. TiTiler remains the default and is unchanged.

Implements #158.

What it does

• New per-layer option cogRendererMode on the COG tab (titiler default / deckRaster). It only takes effect in deck.gl missions; in Leaflet missions the layer falls back to TiTiler, and the field is hidden entirely from the configure UI (not just disabled).
• When set to deckRaster in a deck.gl mission, the COG is read directly (HTTP range requests) and rendered on the GPU:
  • Single-band: named colormap + min/max stretch. Colors come from the repo's existing js-colormaps evaluate_cmap, so the client render matches TiTiler's colormap_name (including _r reversed variants). NaN nodata is discarded (transparent).
  • Multi-band uint (RGB/RGBA): displayed as true color directly (no colormap). This goes beyond the single-band scope in Add deck.gl-raster as a client-side COG renderer option (deck missions only) #158 — it's a small addition so true-color COGs (e.g. Sentinel-2 TCI) also render client-side; noted as pulling that follow-up forward.
• Live updates: changing the colormap or the min/max re-renders in place with no tile-server request (GPU module props via updateTriggers).
• The existing colormap/rescale controls drive it — no new UI.

How it works

• shouldUseDeckRaster(engine, type, layer) gates the deck branch of makeTileLayer(); when false, the existing TiTiler path runs untouched.
• ColormappedCOGLayer (a COGLayer subclass) supplies its own getTileData/renderTile. This is required because the library's default pipeline auto-inference only supports unsigned-integer COGs and throws for float (the common scientific case). The custom loader uploads single-band data as r32float and composes [CreateTexture, FilterNaN, LinearRescale, Colormap]; multi-band uint is uploaded as rgba8unorm and displayed via [CreateTexture, FilterBlack]. Overview selection (finer tiles at higher zoom) is handled by the base layer.
• deck.gl bumped to ^9.3 and luma.gl to ^9.3.2 (peer requirements of the new packages); adds @developmentseed/deck.gl-geotiff, @developmentseed/deck.gl-raster, @developmentseed/morecantile. A pruned focus-trap-react (USWDS build dep) is restored and .npmrc pins legacy-peer-deps for a pre-existing peer conflict.

Testing

• Unit tests (Playwright, tests/unit/): colormap LUT parity with evaluate_cmap, the routing decision, the configure-UI field gating, the colormap-override precedence, the pipeline composition, and the live-update handlers.
• Verified end-to-end in a running deck.gl mission (browser, network panel):
  • A single-band float COG (CMIP6 tasmax) renders with the configured colormap + min/max; oceans (NaN) transparent; zero tile-server tile requests.
  • Changing colormap and min/max both re-render live with zero tile-server requests.
  • A multi-band true-color COG (Sentinel-2 TCI) renders in RGB with correct zoom refinement across its overview pyramid.
  • Existing TiTiler COG layers and Leaflet missions are unaffected.

Known follow-ups (out of scope here)

• The colormap legend swatch is still fetched from TiTiler (/colorMaps) — shared legend/UI infra, independent of the renderer; could be rendered from local js-colormaps for full decoupling.
• Multi-band pass-through assumes 8-bit samples.
• Single-band float uses nearest-neighbor sampling (blocky when magnified past native resolution) because float linear filtering isn't guaranteed in WebGL2; could opt into linear filtering where OES_texture_float_linear is available.
• RGB nodata uses a black-pixel discard heuristic.

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