Coordinator-directed final cleanup before the user gate; none behavioral:
1. MeshExtractor public surface narrowed to the cross-assembly entry
points App actually calls (PrepareMeshData, PrepareCellStructMeshData,
CollectParts, ComputeBounds); PrepareSetupMeshData,
CollectEmittersFromScript, PrepareGfxObjMeshData,
PrepareEnvCellMeshData, PrepareCellStructEdgeLineData back to private
(internal dispatch, only reached via PrepareMeshData).
2. sideStagedSink constructor parameter is now REQUIRED (no default;
type stays nullable for a conscious null): a bake tool that forgot
the sink would silently lose particle-preload meshes.
3. AcDream.Content.csproj gains TreatWarningsAsErrors + LangVersion
latest (parity with AcDream.Core.csproj). Surfaced zero warnings.
4. Dead usings removed from ObjectMeshManager.cs (BCnEncoder.*,
SixLabors.*) — the inline decode moved out in Task 4.
5. Doc fixes: ObjectMeshData.cs cross-assembly <see cref> ->
plain text (Content can't resolve App types); IDatReaderWriter.cs
stale Phase O-T7 'both in this namespace' sentence rewritten.
6. Stale test doc comments updated to MeshExtractor.PrepareGfxObjMeshData
(StipplingSurfaceEquivalenceTests, Issue119UpNullGfxObjDumpTests) —
comments only, no code/assertion changes.
dotnet build green (0 warnings in Content under warnings-as-errors);
full test suite 4059 passed / 0 failed / 4 skipped.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>