fix(deck.gl-geotiff): fill MultiCOGLayer edge-tile padding with nodata

[earlybard]

What I am changing

MultiCOGLayer edge tiles now get their padding rewritten to the file's nodata value before upload, in both the primary and the stitched secondary path, so a nodata filter throws it away along with the real nodata. Files without a nodata value are left alone.

How you can test it

Any nodata-stamped COG that isn't a whole number of tiles wide. DEA's public Sentinel-2 ARD works, but it's Int16 so you need #650 as well:

const scene =
  "https://dea-public-data.s3.ap-southeast-2.amazonaws.com/baseline/ga_s2am_ard_3/55/HFB/2026/01/03/20260103T012735/ga_s2am_nbart_3-2-1_55HFB_2026-01-03_final_band";
new MultiCOGLayer({
  id: "s2",
  sources: {
    red: { url: `${scene}04.tif` },
    green: { url: `${scene}03.tif` },
    blue: { url: `${scene}02.tif` },
  },
  composite: { r: "red", g: "green", b: "blue" },
  renderPipeline: [
    { module: FilterNoDataVal, props: { value: -999 } },
    { module: LinearRescale, props: { rescaleMin: 0, rescaleMax: 3000 } },
  ],
});

Zoom out until the coarse overviews draw. On main there's a black band past the scene's right and bottom edges; with this it's transparent. Linear sampling still leaves a one-texel dark fringe where nodata blends into data; #640's bandSampler: nearest fixes that.

Related Issues

Related to #580, which clips the tile geometry to the array extent. This fixes the samples instead, so the two stack fine.

AI disclosure: written with Claude Code as a code assistant, reviewed by me.