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.Content/CharGen/ChargenAppearanceCatalog.cs

@@ -0,0 +1,105 @@
+using System.Collections.Concurrent;
+using System.Collections.Frozen;
+using AcDream.Core.CharGen;
+using DatClothingTable = DatReaderWriter.DBObjs.ClothingTable;
+using DatPalSet = DatReaderWriter.DBObjs.PalSet;
+using DatCloObjectEffect = DatReaderWriter.Types.CloObjectEffect;
+using DatCloSubPalette = DatReaderWriter.Types.CloSubPalette;
+
+namespace AcDream.Content.CharGen;
+
+/// <summary>
+/// DAT-backed <see cref="IChargenPalSetSource"/> / <see cref="IChargenClothingTableSource"/>
+/// implementation: reads PalSet (0x0F......) and ClothingTable (0x19......)
+/// dat objects on demand and projects them into <see cref="ChargenAppearanceFactory"/>'s
+/// pure Core types, matching <c>ChargenTableReader</c>'s "no Chorizite leak"
+/// discipline for everything it returns. Both lookups cache by dat id — a
+/// live preview re-composes on every appearance change, and the same
+/// PalSet/ClothingTable ids repeat constantly across heritages, genders, and
+/// re-selections within one session.
+/// </summary>
+public sealed class ChargenAppearanceCatalog : IChargenPalSetSource, IChargenClothingTableSource
+{
+    private readonly IDatReaderWriter _dats;
+    private readonly ConcurrentDictionary<uint, ChargenPalSet?> _palSets = new();
+    private readonly ConcurrentDictionary<uint, ChargenClothingTable?> _clothingTables = new();
+
+    public ChargenAppearanceCatalog(IDatReaderWriter dats)
+    {
+        _dats = dats ?? throw new ArgumentNullException(nameof(dats));
+    }
+
+    public ChargenPalSet? TryGetPalSet(uint palSetId) =>
+        _palSets.GetOrAdd(palSetId, LoadPalSet);
+
+    public ChargenClothingTable? TryGetClothingTable(uint clothingTableId) =>
+        _clothingTables.GetOrAdd(clothingTableId, LoadClothingTable);
+
+    private ChargenPalSet? LoadPalSet(uint id)
+    {
+        DatPalSet? palSet = _dats.Get<DatPalSet>(id);
+        if (palSet is null)
+            return null;
+
+        var ids = new uint[palSet.Palettes.Count];
+        for (int i = 0; i < palSet.Palettes.Count; i++)
+            ids[i] = palSet.Palettes[i].DataId;
+        return new ChargenPalSet(Array.AsReadOnly(ids));
+    }
+
+    private ChargenClothingTable? LoadClothingTable(uint id)
+    {
+        DatClothingTable? table = _dats.Get<DatClothingTable>(id);
+        if (table is null)
+            return null;
+
+        var baseEffects = new Dictionary<uint, ChargenClothingBaseEffect>(
+            table.ClothingBaseEffects.Count);
+        foreach (var pair in table.ClothingBaseEffects)
+            baseEffects[pair.Key.DataId] = ProjectBaseEffect(pair.Value.CloObjectEffects);
+
+        var templates = new Dictionary<uint, ChargenClothingPaletteTemplate>(
+            table.ClothingSubPalEffects.Count);
+        foreach (var pair in table.ClothingSubPalEffects)
+            templates[pair.Key] = ProjectPaletteTemplate(pair.Value.CloSubPalettes);
+
+        return new ChargenClothingTable(
+            baseEffects.ToFrozenDictionary(),
+            templates.ToFrozenDictionary());
+    }
+
+    private static ChargenClothingBaseEffect ProjectBaseEffect(
+        IReadOnlyList<DatCloObjectEffect> objectEffects)
+    {
+        var partChanges = new List<ChargenAnimPartChange>(objectEffects.Count);
+        var textureChanges = new List<ChargenTextureChange>();
+        foreach (DatCloObjectEffect effect in objectEffects)
+        {
+            var partIndex = (byte)effect.Index;
+            partChanges.Add(new ChargenAnimPartChange(partIndex, effect.ModelId.DataId));
+            foreach (var tex in effect.CloTextureEffects)
+            {
+                textureChanges.Add(new ChargenTextureChange(
+                    partIndex, tex.OldTexture.DataId, tex.NewTexture.DataId));
+            }
+        }
+        return new ChargenClothingBaseEffect(
+            Array.AsReadOnly(partChanges.ToArray()),
+            Array.AsReadOnly(textureChanges.ToArray()));
+    }
+
+    private static ChargenClothingPaletteTemplate ProjectPaletteTemplate(
+        IReadOnlyList<DatCloSubPalette> subPalettes)
+    {
+        var choices = new ChargenClothingSubPaletteChoice[subPalettes.Count];
+        for (int i = 0; i < subPalettes.Count; i++)
+        {
+            DatCloSubPalette sub = subPalettes[i];
+            var ranges = new ChargenClothingSubPaletteRange[sub.Ranges.Count];
+            for (int j = 0; j < sub.Ranges.Count; j++)
+                ranges[j] = new ChargenClothingSubPaletteRange(sub.Ranges[j].Offset, sub.Ranges[j].NumColors);
+            choices[i] = new ChargenClothingSubPaletteChoice(sub.PaletteSet.DataId, Array.AsReadOnly(ranges));
+        }
+        return new ChargenClothingPaletteTemplate(Array.AsReadOnly(choices));
+    }
+}