docs(palette): verify balanced warm umber soil in 3d presets (#201)

[BharathASL]

Description

This pull request completes the technical verification and documentation for Issue #201, resolving the two acceptance criteria carried over from parent Issue #37 following the soil palette standardization in PR #198 (commit 3348ffc):

1. 3D Multiblock Terrain Preset Inspection: Verified Balanced Warm Umber soil palette assets (dirt, coarse_dirt, dirt_path_top, dirt_path_side, grass_block_side, grass_block_side_overlay) in TextureStudio 3D terrain presets (adaptive_cliff_3x3, adaptive_platform_3x3, adaptive_wall_3x3, adaptive_pillar_1x4). Confirmed dominant base tone separation between dirt (#c77d38) and coarse_dirt (#9e5d22) provides ΔY = 11.88 Rec.709 luminance points (1.78x ratio) under directional key lighting, preventing coarse dirt from reading as shadow patches. Validated 15/16th height step depression (0.9375) and UV clamping on dirt_path_top/dirt_path_side, zero seam discontinuity (Δ = 0) across 3D adjacent cube boundaries, and confirmed zero double-tinting on grass side overhang via 100% transparent grass_block_side_overlay.svg.
2. Trailer Footage Testing & Substituted Methodology: Documented that no reference trailer video files exist in the repository or local environment. Verified the palette against official cinematic trailer reference stills and aesthetic color metrics using 512×512 rasterized multi-block cliff-face and path-cut composites, confirming rejection of desaturated beige Candidate A and oversaturated Candidate C while settling Balanced Warm Umber.

Introduces a self-contained, deterministic automated test suite in tools/test/soil-palette-3d.test.mjs wired into package.json (test:soil-palette-3d) and .github/workflows/ci.yml, covering hex contracts, Rec.709 luminance metrics, seam rules, overlay transparency, and skippable sibling checks. Adds comprehensive audit record docs/audits/issue-201-soil-palette-3d-verification.md and updates CHANGELOG.md.

Closes #201

Affected Assets

• docs/audits/issue-201-soil-palette-3d-verification.md
• tools/test/soil-palette-3d.test.mjs
• CHANGELOG.md
• package.json
• .github/workflows/ci.yml

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Type of Change

• feat: New vector texture master, blockstate, or compiler capability
• fix: Tiling fix, palette correction, or bugfix
• docs: Documentation improvement
• chore / refactor: Maintenance, dependencies, or codebase cleanup

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Contributor Checklist

Please check all applicable boxes before requesting review:

Vector Texture Standards (if adding/modifying SVGs)

• Authored as a clean $512\times512$ SVG (viewBox="0 0 512 512").
• Primary shapes are aligned to the $32\text{px}$ texel grid ($16\times16$ grid).
• Seamless Toroidal Tiling: Checked and verified that elements wrapping across $X$ and $Y$ edges align perfectly without seams or chopped shapes.
• Ore Consistency: If adding an ore texture, the stone background geometry and corner radius (rx) match textures/block/stone.svg exactly.
• Free of leftover AI generation comments, unnecessary editor namespaces, or embedded raster images.

Build & Verification

• Ran npm run build locally and verified that the pack compiles successfully.
• Verified textures in-game or inspected the rasterized PNG outputs in dist/.

Git Hygiene & Standards

• Commit message(s) follow Conventional Commits (e.g., feat(textures): ...).
• Every commit is signed off with the Developer Certificate of Origin (git commit -s).
• Branch is rebased cleanly onto latest main with no merge commits.
• Formatting complies with .editorconfig (2-space indent, LF endings, trailing newline).

[ninja6-agent]

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[ninja6-agent]

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