chore: checkpoint web Blender migration source, tools and docs

Accumulated uncommitted work: GHOST Web backend, WebGL/GPU web layer,
web workflow engine and protocol, tooling, docs and task records.
Large generated evidence, user-testing archives, build snapshots and
imported test assets remain untracked.

Co-Authored-By: Claude Code <noreply@anthropic.com>

web/protocol/mesh-cache.ts

@@ -1,6 +1,6 @@
 import type { MeshGeometryBuffer, WebEngineLODLevelResult } from "./web-engine";
 
-const bufferFields = ["positions", "indices", "normals", "triangleCornerIndices", "uvs", "colors", "triangleMaterialIndices"] as const;
+const bufferFields = ["positions", "indices", "normals", "splitNormals", "triangleCornerIndices", "uvs", "colors", "triangleMaterialIndices"] as const;
 type BufferField = typeof bufferFields[number];
 
 interface BufferDescriptor {
@@ -117,6 +117,7 @@ export function decodeLODGeometry(data: ArrayBuffer): WebEngineLODLevelResult[]
         positions,
         indices,
         normals: decoded.get("normals"),
+        splitNormals: decoded.get("splitNormals"),
         triangleCornerIndices: decoded.get("triangleCornerIndices"),
         uvs: decoded.get("uvs"),
         colors: decoded.get("colors"),