feat(chargen): Campaign CC slice CC6a — index→ObjDesc factory + preview renderer foundation

Delivers the CC6a foundation half of the chargen 3D preview: the missing
index->ObjDesc appearance factory the campaign plan's acdream-seams
section named, plus a static-pose offscreen renderer following
PrivateEntityViewportRenderer's proven paperdoll/appraisal architecture.
Page mount, spin/color-wheel controls, and rotate/zoom behavior stay out
of scope per the CC4-parallel worktree contract (CC6b, after CC4 merges).

Core (src/AcDream.Core/CharGen/, pure, no Chorizite on public surfaces):
ChargenAppearanceFactory.TryCompose ports gmCG3DView::Update @0x004EE9D0's
ObjDesc rebuild in its exact decompiled order - base body, hair style,
clothing in retail's own Headgear/Trousers/Shirt/Footwear order (not the
UI tab order or the wire's field order, both of which differ), eyes
(bald-aware), nose, mouth, then the unconditional skin subpalette, hair
color, eye color. ChargenPalSetMath ports PalSet::GetPaletteID's
shade-to-index formula, cross-checked three ways (decomp control flow,
ACE's PaletteSet.GetPaletteID "Taken from acclient.c" citation, ACViewer's
identical slider math). ChargenPalSet/ChargenClothingTable are pure
projections behind IChargenPalSetSource/IChargenClothingTableSource so the
factory itself never touches a dat.

Content (src/AcDream.Content/CharGen/): ChargenAppearanceCatalog is the
cached dat-backed implementation of those two source interfaces, mirroring
ChargenTableReader's no-leak discipline.

App (src/AcDream.App/Rendering/): ChargenPreviewRenderer is a third facade
over PrivateEntityViewportRenderer beside PaperdollViewportRenderer and
CreatureAppraisalViewportRenderer - no existing rendering file touched.
ChargenPreviewCamera carries the four retail-verbatim per-heritage eye
profiles from gmCGAppearancePage::Update @0x0047E8F0 (cross-checked
against ZoomIn/ZoomOut's identical literals) plus the recovered rotation
(3.0 s/revolution) and zoom-tween (0.6 s, reconstructed from the
decompiler's garbled float literals - the plan's own "measure if it
matters" note is resolved, not garbled beyond recovery). Rotation applies
to the character model, not the camera, per gmCGAppearancePage::DoRotation.
ChargenPreviewEntityBuilder resolves Setup/GfxObj/Surface/Animation itself
(there is no live entity yet), reusing DatLiveEntityProjectionMaterializer's
surface-override algorithm and RetailPaperdollPoseApplicator's held-pose
technique, generalized to chargen's per-heritage rest-pose DID.

Two register rows filed: TS-83 (the plan-named CC6a static-pose-vs-retail-
idle-loop staging, CC6b to retire) and TS-82 (measured, not assumed - the
un-ported clothing Setup-substitution fallback chain costs nothing for the
9 standard heritages with clothing UI, but Undead's default gear choices
genuinely lack ClothingBaseEffects coverage for Undead's own body Setup).

Tests: ChargenPalSetMathTests, ChargenAppearanceFactoryTests (hand-built
fixtures), ChargenAppearanceCatalogInstalledDatTests (installed-DAT sweep,
all 26 heritage/gender combinations, zero missing PalSet/ClothingTable
ids), ChargenPreviewCameraTests, ChargenPreviewEntityBuilderTests
(installed-DAT-gated, proves a real 34-part Aluvian mesh resolves).
Core.Tests 4767/1 skip, Content.Tests 146/0, App.Tests 5121/6 skips - all
pre-existing skips, zero failures, full solution Release build green.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/AcDream.App/Rendering/ChargenPreviewRenderer.cs

@@ -0,0 +1,80 @@
+using AcDream.App.Rendering.Wb;
+using AcDream.App.UI;
+using AcDream.Core.Lighting;
+using AcDream.Core.World;
+
+namespace AcDream.App.Rendering;
+
+/// <summary>
+/// Chargen-specific facade over the shared private creature viewport
+/// (<see cref="PrivateEntityViewportRenderer"/>) — CC6a's foundation half of
+/// the campaign plan's "chargen preview renderer" deliverable. Mirrors
+/// <see cref="PaperdollViewportRenderer"/>'s shape exactly, with a
+/// heading-capable <see cref="ChargenPreviewViewportCamera"/> in place of the
+/// paperdoll's fixed one.
+///
+/// <para>
+/// <b>NOT wired here (CC6b, after CC4 merges per the campaign's parallelism
+/// contract):</b> mounting into the authored Appearance/Summary viewport ids
+/// (<c>0x100003bb</c> / <c>0x10000406</c>), spin/color-wheel controls, and
+/// the rotate/zoom buttons. This class is a standalone, composition-root-
+/// agnostic renderer — nothing in <c>AcDream.App/UI/Layout/</c> or
+/// <c>RetailUiRuntime.cs</c> references it yet.
+/// </para>
+///
+/// <para>
+/// <b>Register row (staged deviation, retired by CC6b):</b> retail plays a
+/// live 30fps idle loop in the preview
+/// (<c>gmCG3DView</c>'s <c>m_didAnimation</c>/<c>m_didAnimArray</c>,
+/// <c>set_sequence_animation</c>, distinct from the STATIC
+/// <c>m_didAnimationRest</c> this class's entity builder uses). CC6a holds
+/// the static rest-pose final frame only — see
+/// <c>docs/architecture/retail-divergence-register.md</c>.
+/// </para>
+/// </summary>
+internal sealed class ChargenPreviewRenderer :
+    IUiViewportRenderer,
+    IDisposable
+{
+    private readonly PrivateEntityViewportRenderer _renderer;
+    private readonly ChargenPreviewViewportCamera _camera;
+
+    internal ChargenPreviewRenderer(
+        IWorldPassScope scope,
+        AcDream.App.Rendering.Gpu.IGpuDevice device,
+        ICurrentGpuFrameSource frames,
+        WbDrawDispatcher dispatcher,
+        SceneLightingUboBinding lightUbo,
+        IEntityTextureLifetime textureLifetime,
+        IWbMeshAdapter meshAdapter,
+        uint heritageId = 0u)
+    {
+        _camera = new ChargenPreviewViewportCamera(heritageId);
+        _renderer = new PrivateEntityViewportRenderer(
+            scope,
+            device,
+            frames,
+            dispatcher,
+            lightUbo,
+            textureLifetime,
+            meshAdapter,
+            ChargenPreviewEntityBuilder.PreviewRenderId,
+            _camera,
+            "chargen preview");
+    }
+
+    public bool TextureIsBottomUp => _renderer.TextureIsBottomUp;
+
+    /// <summary>
+    /// Re-derives the fixed per-heritage camera eye
+    /// (<see cref="ChargenPreviewCamera.ResolveDefaultEye"/>) — call whenever
+    /// the selected heritage changes, BEFORE the next <see cref="Render"/>.
+    /// </summary>
+    public void SetHeritage(uint heritageId) => _camera.SetHeritage(heritageId);
+
+    public void SetPreview(WorldEntity? entity) => _renderer.SetEntity(entity);
+
+    public uint Render(int width, int height) => _renderer.Render(width, height);
+
+    public void Dispose() => _renderer.Dispose();
+}