feat(chargen): Campaign CC slice CC6b-MOUNT — Appearance page + preview mount

The page-mount half CC6b-PRE deferred: CharacterCreationAppearancePage
(gender buttons, Face/Clothes sub-tabs, nine spin controls with retail's
decrement/increment/select-as-current-part OnClickAt zones, nine color
swatches, shade scrollbar, zoom/rotate wiring) plus ChargenPreviewController,
which bridges the ChargenPreviewRenderer/ChargenPreviewZoomController
camera-injection gap CC6a/CC6b-PRE left open and mounts as the third private
creature viewport beside paperdoll/creature-appraisal.

Color-wheel scouting (campaign risk item 4): live-DAT probe found every
color-wheel-family id resolves through existing DatWidgetFactory mappings
(Button/Scrollbar/generic fallback) — no new widget type needed.

The @140355 gender-flip-on-init oddity (risk item 5): resolved via decomp
alone — gmCharGenMainUI's own ctor calls CharGenState::RandomizeCharacter
before any page constructs, so retail's chargen screen is never actually
blank on open; the Appearance page's gender-flip code always fires against
a real, randomly-rolled gender. Filed AP-214 (acdream doesn't port
RandomizeCharacter this round, so it opens honestly blank instead) and
AP-215 (two narrow visual substitutions: swatch .Selected highlight vs
retail's separate overlay, ordinal labels vs retail's icon-only spins).

AD-101 retired: the Heritage page's auto-gender-select interim default is
deleted now that the Appearance page's real gender buttons exist. TS-82
narrowed to Summary-only.

Scope addendum: ChargenPreviewRotationController's parameterless-constructor
default changes from 0f to a new RetailDefaultHeadingDegrees=180f constant
(retail's InitializePage override, not the ctor's raw 0) — every real
gmCG3DView owner converges on 180 before its first frame, so a controller
defaulting to 0 was a trap for future consumers.

Runtime 1713/0, Core 4786/1 skip, Content 147/0, App 5220/3 skips (Release,
ACDREAM_PROBE_LIVE_MOUNT=1) — zero failures across two clean full-solution
runs; the one Core.Net.Tests NakEmissionTests flake observed on a third run
is the same pre-existing, previously-documented timing flake (zero files
under src/AcDream.Core.Net/ touched, passes 100% in isolation).

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

src/AcDream.App/Composition/FrameRootComposition.cs

@@ -539,7 +539,8 @@ internal sealed class FrameRootCompositionPhase
             renderFrameResources,
             new PrivateEntityViewportFrameGroup(
                 live.PaperdollPresenter,
-                live.CreatureAppraisalPresenter),
+                live.CreatureAppraisalPresenter,
+                live.ChargenPreviewController),
             retainedGameplayUi,
             // The ImGui developer-tools frontend was removed at Campaign V
             // slice V11; this optional hook is unbound until a follow-up