fix(chargen): Campaign CC CC6b-PRE review fix round — F1-F7 + F11 concession rewrite

F1 (BLOCKING, doc-only) — the idle-by-default rationale rested on an unsound
"uninitialized C++ member defaults to 0" argument (heap operator-new memory
is indeterminate, not zero). Verified and replaced with the real evidence:
gmCGAppearancePage::InitializePage @0x0047FDD0 writes an EXPLICIT
this->m_bZoomedIn = 0; at 0x004802C3, immediately after that same function
points the camera at the zoomed-IN per-heritage eye (0x00480286-0x0048029E).
Fixed in all three places: the register's TS-83 retirement clause,
ChargenPreviewAnimator's class doc, ChargenPreviewZoomController.IsZoomedIn's
doc. Recorded the retail quirk this implies: the character starts framed
close-up while not-zoomed-in, so the first Zoom In click (once mounted)
tweens close-eye->close-eye (visually null) while still freezing the
animation — the port reproduces this faithfully.

F2 — ChargenPreviewZoomController and ChargenPreviewAnimator kept
independent _zoomedIn bools synced only via a nullable animator parameter,
risking desync. Retail's m_bZoomedIn is a single field gating both camera
and animation, so the fix makes the animator the sole state owner:
ChargenPreviewZoomController now takes its ChargenPreviewAnimator as a
required constructor dependency, IsZoomedIn reads straight through to it,
and ZoomIn/ZoomOut no longer take a parameter at all — there is no second
bool left to disagree.

F3 — documented the DoRotation counter-clockwise branch's x87-stack
decompiler artifact (BN renders x87_r7_1 = x87_r6_3 at 0x0047CAEB, which
would store delta-degrees instead of the timestamp for CCW only); the port
already stores "now" in both branches, cited against
feedback_bn_decomp_field_names.md.

F4 — ChargenPreviewAnimator.ApplyIdleFrame now double-buffers two
List<MeshRef> instead of allocating fresh every 30fps tick.

F5 — filed docs/ISSUES.md #402 tracking the RetailAnimationCyclePlayback /
LiveEntityAnimationPresenter duplication as an owned post-CC follow-up,
referenced from the new type's own doc.

F6 — reworded the ChargenPreviewEntityBuilder.TryBuild "byte-identical"
claim to result-identical (TryBuildAnimated now also resolves the idle DID
and loads the idle Animation before the wrapper discards them).

F7 — added the missing clockwise >360 clamp test (readable decomp
polarity, unlike F3's CCW artifact).

ALSO — rewrote the CC6b ledger row's m_alternateSetupID MUST-COVER note per
the reviewer's F11 concession: all five write sites belong to gmBarberUI
(the post-creation barber shop), not gmCGAppearancePage, which has no
option-checkbox-equivalent field at all. Added the enclosing-function
citations and an explicit directive that CC6b-mount must NOT build a
crown/no-flame checkbox on the Appearance page.

Tests: ChargenPreviewRotationControllerTests +1 (10 total),
ChargenPreviewZoomControllerTests +2 and every case rewritten for the
required-animator constructor (9 total). Core.Tests 4786/1 skip (unchanged),
Content.Tests 147/0, App.Tests 5152/6 skips (+3) — zero failures in
isolation, full solution Release build green. Two pre-existing flakes
observed across repeated full-solution runs, neither caused by this round
and neither reproducing standalone: Core.Net.Tests' NakEmissionTests loss
soak, and Content.Tests' DecodedTextureCacheTests concurrency race.

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

src/AcDream.App/Rendering/ChargenPreviewAnimator.cs

@@ -26,6 +26,17 @@ namespace AcDream.App.Rendering;
 /// at frame 0 on every transition INTO the playing state for the same
 /// reason: <c>set_sequence_animation</c>'s <c>arg3=1</c> clears the sequence
 /// before appending, so every <c>StartAnimation</c> call restarts the clip.
+/// The DEFAULT-false claim itself rests on <c>gmCGAppearancePage::InitializePage
+/// @ 0x0047FDD0</c>'s explicit <c>this-&gt;m_bZoomedIn = 0;</c> at
+/// <c>0x004802C3</c> — written immediately after that same function sets the
+/// camera to the zoomed-IN per-heritage eye (<c>0x00480286-0x0048029E</c>),
+/// not from the ctor simply never touching the field (heap <c>operator new</c>
+/// memory is indeterminate, not zero — that argument doesn't hold on its
+/// own). One retail quirk this implies: the character starts framed close-up
+/// AND not-zoomed-in at the same time, so the FIRST Zoom In click (once
+/// mounted) tweens close-eye→close-eye — visually null — while still
+/// freezing the animation; the port reproduces this faithfully rather than
+/// treating it as a bug.
 /// </para>
 ///
 /// <para>
@@ -47,6 +58,15 @@ internal sealed class ChargenPreviewAnimator
     private float _currFrame;
     private bool _zoomedIn;
 
+    // Double-buffered so a 30fps Tick doesn't allocate a fresh List<MeshRef>
+    // every frame: one buffer is whatever Entity.MeshRefs currently points
+    // at (potentially still being read by the renderer's own Render() call
+    // for this frame), the other is safe to Clear()+refill for the NEXT
+    // tick and only gets published once fully populated.
+    private readonly List<MeshRef> _meshRefsBufferA = [];
+    private readonly List<MeshRef> _meshRefsBufferB = [];
+    private bool _nextBufferIsA = true;
+
     public ChargenPreviewAnimator(ChargenPreviewAnimatedBuild build)
     {
         _build = build ?? throw new ArgumentNullException(nameof(build));
@@ -112,7 +132,9 @@ internal sealed class ChargenPreviewAnimator
     {
         DatReaderWriter.DBObjs.Animation animation = _build.IdleAnimation!;
         IReadOnlyList<ChargenPreviewDrawablePart> parts = _build.DrawableParts;
-        var meshRefs = new List<MeshRef>(parts.Count);
+        List<MeshRef> meshRefs = _nextBufferIsA ? _meshRefsBufferA : _meshRefsBufferB;
+        _nextBufferIsA = !_nextBufferIsA;
+        meshRefs.Clear();
         foreach (ChargenPreviewDrawablePart part in parts)
         {
             bool resolved = RetailAnimationCyclePlayback.TryInterpolatePart(

src/AcDream.App/Rendering/ChargenPreviewEntityBuilder.cs

@@ -144,10 +144,14 @@ internal static class ChargenPreviewEntityBuilder
     /// resolved body Setup isn't in the dat source (a corrupted/incomplete
     /// install — the same failure shape
     /// <see cref="DatLiveEntityProjectionMaterializer"/> treats as "drop this
-    /// spawn"). Unchanged since CC6a — a thin wrapper over
-    /// <see cref="TryBuildAnimated"/> that keeps this method's existing
-    /// callers' behavior byte-identical. New code that wants retail's true
-    /// default (idle loop playing) should call
+    /// spawn"). Unchanged since CC6a for its RESULT — a thin wrapper over
+    /// <see cref="TryBuildAnimated"/> that returns exactly the same
+    /// <c>WorldEntity</c> (rest-posed) this method's existing callers already
+    /// expect; ALL 3 of those callers' tests still pass unmodified. Not
+    /// byte-identical internally any more — <see cref="TryBuildAnimated"/>
+    /// also resolves the idle DID and loads the idle Animation before this
+    /// wrapper discards them, extra dat work the pre-CC6b method never did.
+    /// New code that wants retail's true default (idle loop playing) should call
     /// <see cref="TryBuildAnimated"/> and wrap the result in a
     /// <see cref="ChargenPreviewAnimator"/> instead.
     /// </summary>

src/AcDream.App/Rendering/ChargenPreviewRotationController.cs

@@ -84,7 +84,19 @@ internal sealed class ChargenPreviewRotationController
     /// <c>[0, 360)</c> — not a full modulo loop; retail's own tail only
     /// adds/subtracts 360 once (pseudo-C ~0x0047caf3-0x0047cb31), which is
     /// exactly enough for any realistic per-frame delta and is reproduced
-    /// here verbatim rather than "improved" into a `%=`.
+    /// here verbatim rather than "improved" into a `%=`. Fix round F3: Binary
+    /// Ninja literally renders <c>x87_r7_1 = x87_r6_3</c> at <c>0x0047CAEB</c>
+    /// inside the counter-clockwise branch — reassigning the local that held
+    /// the "now" timestamp to the just-computed delta-degrees value — which
+    /// would make the <c>0x0047CB3D</c> store into <c>m_dLastRotateTime</c>
+    /// write delta-degrees instead of the timestamp for CCW only; that is an
+    /// x87-FPU-stack modeling artifact of the decompiler, not real retail
+    /// behavior (a shipped feature where every counter-clockwise rotation
+    /// visibly diverges from clockwise is implausible, and
+    /// <c>claude-memory/feedback_bn_decomp_field_names.md</c> names exactly
+    /// this x87-stack-register mislabeling as a known decompiler artifact
+    /// class), so this port stores <c>now</c> into <c>_lastRotateTime</c>
+    /// unconditionally in BOTH directions.
     /// </summary>
     public void Tick(double now)
     {

src/AcDream.App/Rendering/ChargenPreviewZoomController.cs

@@ -13,6 +13,24 @@ namespace AcDream.App.Rendering;
 /// finishes (see <see cref="ChargenPreviewAnimator"/>'s own doc comment).
 ///
 /// <para>
+/// <b>One owner of the zoom state (fix round F2):</b> retail's
+/// <c>m_bZoomedIn</c> is a SINGLE field on <c>gmCGAppearancePage</c> that
+/// gates both the camera target AND the animation swap — there is no way
+/// for retail's own camera and animation to disagree about which zoom state
+/// they're in. The first cut of this port kept two independent bools (one
+/// here, one on <see cref="ChargenPreviewAnimator"/>) synced only by
+/// <see cref="ZoomIn"/>/<see cref="ZoomOut"/> calling a NULLABLE animator
+/// parameter — a null pass, or any direct
+/// <see cref="ChargenPreviewAnimator.SetZoomedIn"/> call bypassing this
+/// controller, would desync the camera's target from the animation's pose.
+/// This class now takes its <see cref="ChargenPreviewAnimator"/> as a
+/// REQUIRED constructor dependency and <see cref="IsZoomedIn"/> reads
+/// straight through to <see cref="ChargenPreviewAnimator.IsZoomedIn"/> — the
+/// animator is the sole state owner, matching retail's own single-field
+/// design, and there is no longer a second bool that could disagree with it.
+/// </para>
+///
+/// <para>
 /// Retail drives <see cref="Tick"/> once per frame from a global-message-3
 /// tick while <c>m_bShouldZoomAnimate</c> is set
 /// (<c>gmCGAppearancePage::ListenToGlobalMessage @ 0x0047CED0</c>); the
@@ -38,59 +56,68 @@ internal sealed class ChargenPreviewZoomController
     private const double InvalidDurationSentinel = -0.1;
 
     private readonly uint _heritageId;
+    private readonly ChargenPreviewAnimator _animator;
     private Vector3 _startEye;
     private Vector3 _targetEye;
     private double _animStartTime;
     private double _animDuration;
     private bool _shouldAnimate;
-    private bool _zoomedIn;
 
-    public ChargenPreviewZoomController(uint heritageId, ChargenPreviewCamera camera)
+    public ChargenPreviewZoomController(uint heritageId, ChargenPreviewCamera camera, ChargenPreviewAnimator animator)
     {
         ArgumentNullException.ThrowIfNull(camera);
+        ArgumentNullException.ThrowIfNull(animator);
         _heritageId = heritageId;
         Camera = camera;
+        _animator = animator;
     }
 
     public ChargenPreviewCamera Camera { get; }
 
-    /// <summary>Mirrors retail's <c>m_bZoomedIn</c> — false (not zoomed in)
-    /// is the ctor-implicit default, matching <see cref="ChargenPreviewAnimator"/>'s
-    /// own default (see that class's doc comment for the shared citation).</summary>
-    public bool IsZoomedIn => _zoomedIn;
+    /// <summary>
+    /// Mirrors retail's <c>m_bZoomedIn</c> — a straight read-through to
+    /// <see cref="ChargenPreviewAnimator.IsZoomedIn"/> (see this class's own
+    /// "one owner" doc above), which itself defaults false per
+    /// <c>gmCGAppearancePage::InitializePage @ 0x0047FDD0</c>'s explicit
+    /// <c>this-&gt;m_bZoomedIn = 0;</c> at <c>0x004802C3</c> — written right
+    /// after that same function points the camera at the zoomed-IN
+    /// per-heritage eye (<c>0x00480286-0x0048029E</c>). One retail quirk
+    /// this produces: the character starts framed close-up while
+    /// NOT-zoomed-in, so the first Zoom In click (once mounted) tweens
+    /// close-eye→close-eye — visually null — while still freezing the
+    /// animation; this port reproduces it faithfully.
+    /// </summary>
+    public bool IsZoomedIn => _animator.IsZoomedIn;
 
     /// <summary>
     /// <c>gmCGAppearancePage::ZoomIn @ 0x0047CF00</c>: no-op if already
     /// zoomed in (retail's own early-return guard). Otherwise starts a tween
     /// from the camera's CURRENT eye to the default (zoomed-IN) per-heritage
-    /// profile and swaps <paramref name="animator"/> to the frozen rest
-    /// pose IMMEDIATELY (<c>gmCG3DView::StopAnimation</c>'s call site,
-    /// pseudo-C ~0x0047d024, precedes the tween's own completion by
-    /// definition — it runs once, synchronously, inside <c>ZoomIn</c>
-    /// itself).
+    /// profile and swaps the animator to the frozen rest pose IMMEDIATELY
+    /// (<c>gmCG3DView::StopAnimation</c>'s call site, pseudo-C ~0x0047d024,
+    /// precedes the tween's own completion by definition — it runs once,
+    /// synchronously, inside <c>ZoomIn</c> itself).
     /// </summary>
-    public void ZoomIn(ChargenPreviewAnimator? animator)
+    public void ZoomIn()
     {
-        if (_zoomedIn)
+        if (IsZoomedIn)
             return;
         StartTween(ChargenPreviewCamera.ResolveDefaultEye(_heritageId));
-        _zoomedIn = true;
-        animator?.SetZoomedIn(true);
+        _animator.SetZoomedIn(true);
     }
 
     /// <summary>
     /// <c>gmCGAppearancePage::ZoomOut @ 0x0047D050</c>: no-op if not
     /// currently zoomed in. Otherwise starts a tween toward the zoomed-OUT
-    /// per-heritage profile and swaps <paramref name="animator"/> back to
-    /// the playing idle loop immediately, mirroring <see cref="ZoomIn"/>.
+    /// per-heritage profile and swaps the animator back to the playing idle
+    /// loop immediately, mirroring <see cref="ZoomIn"/>.
     /// </summary>
-    public void ZoomOut(ChargenPreviewAnimator? animator)
+    public void ZoomOut()
     {
-        if (!_zoomedIn)
+        if (!IsZoomedIn)
             return;
         StartTween(ChargenPreviewCamera.ResolveZoomedOutEye(_heritageId));
-        _zoomedIn = false;
-        animator?.SetZoomedIn(false);
+        _animator.SetZoomedIn(false);
     }
 
     private void StartTween(Vector3 targetEye)

src/AcDream.Core/Physics/RetailAnimationCyclePlayback.cs

@@ -34,7 +34,8 @@ namespace AcDream.Core.Physics;
 /// behavior-preserving mechanical follow-up (not done here — that file is
 /// live, heavily tested production entity-rendering code with zero relation
 /// to this preview-only feature, so touching it is out of this slice's
-/// blast radius by design, not oversight).
+/// blast radius by design, not oversight). Tracked as
+/// <c>docs/ISSUES.md</c> #402 so the follow-up has an owner.
 /// </para>
 /// </summary>
 public static class RetailAnimationCyclePlayback