fix(CT6): fix round — chrome-inclusive host clamp (BLOCKER B1) + 372px mount default

Opus dual-lens review of CT6 (ec50455a) found 1 blocker, 4 should-fix, 5
notes. All applied:

BLOCKER B1 — the shared gmPanelUI host (0x100005FE) IS retail's own
outer window frame, not a content element: its authored 310/372/310/1000
already include the 5px bevel on every side. RetailWindowFrame.Mount was
adding the NineSlice wrapper's OWN 10px chrome inset on top of that
already-chrome-inclusive source, clamping MinWidth to 320 while the
window's actual mounted outer width stayed 310 — silently below its own
minimum until RetailWindowManager.ResizeTo forcibly widened it despite
ResizeX=false. Fixed with a new
RetailWindowFrame.Options.DatConstraintSourceIsOuterFrame opt-out
(chrome inset = 0 for constraint resolution only, value stays
DAT-sourced); MountCharacter sets it true. Mounted clamp is now exactly
the host's four raw values: width fixed 310, height 372..1000. Added a
mount-time invariant (throws if the mounted outer extent falls outside
its own just-computed clamp) that would have caught this at the first
test run.

S4 (campaign-lead ruling) — the window must MOUNT at retail's authored
default, outer 372 (content 362, matching the host's own content parent
0x10000180), not 0x2100002E's own 300x600 content-authoring canvas
(which produced a stale 610px default pre-fix: 600 + 10 chrome inset).
372 is exactly the host's own authored MinHeight — retail opens at its
resize floor and can only be dragged taller. MountCharacter now sets
ContentHeight=362f explicitly. At this default the 9 attribute/vital
rows (180px) overflow the 160px list immediately — retail-correct, not
a regression.

S2 — 0x1000023E and 0x10000533 both author property 0x79
(HideWhenDisabled) TRUE (fixture-verified: BoolValue=true on both). A
fitting list HIDES the scrollbar entirely; it does not draw a full-track
"disabled" thumb. The code was already correct; four wrong descriptions
(plan ledger, CharacterStatController comment, CT7 script, test comment)
are corrected, plus a new IsPresentationVisible assertion pair in the
resize test.

S3 — CharacterTitlesController's `if (listBox.LayoutPolicy is null)`
Anchors fallback was unreachable on both the real DAT and the fixture
(0x10000532/0x10000539 both author HasOriginalParentSize=true, so
LayoutPolicy is always assigned). Deleted; added an InstalledDatFact pin
guarding the deletion against DAT drift.

N4 — renamed NineSlice_ChatShapedConstraints_... to
NineSlice_ContentShapedConstraints_InsetArithmeticClampsProgrammaticResize
(it tested inset arithmetic on a content-shaped source, not chat's real
contract) and added a true chat-contract pin mounting Chrome=Imported
with chat's real 300/100/2000/2000 constraints, asserting no inset
applies.

N5 — corrected the "nothing inferred, no register row" sentences in the
ground-truth doc and plan ledger: they were false pre-fix (the mounted
clamp WAS an inferred double-counted composition); true now that B1
removes the composition.

CT7 script §4 rewritten with exact clamps (no "≈"), the corrected
default-overflow scrollbar behavior, and an absolute starting-height
statement.

Verified: full hermetic solution suite green (15,441 tests, Release,
Lane exclusions per the release gate), InstalledDat lane green across
the whole solution (414 tests, ACDREAM_RUN_INSTALLED_DAT_TESTS=1,
Status!=KnownFailure) including two new pins
(TitlesListAndPage_AuthorHasOriginalParentSize,
Imported_ChatContract_ClampsAtAuthoredBoundsWithNoChromeInset).

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

src/AcDream.App/UI/RetailUiRuntime.cs

@@ -4122,6 +4122,17 @@ public sealed class RetailUiRuntime : IDisposable
         // host 0x100005FE authors MinWidth=310 MinHeight=372 MaxWidth=310
         // MaxHeight=1000 (Min==Max width: no horizontal Resizebar is
         // authored, matching ResizeX=false below).
+        //
+        // CT6 fix round (2026-08-25, BLOCKER B1): host 0x100005FE is not a
+        // content element our NineSlice wrapper adds chrome to — it IS
+        // retail's own outer window frame (5px bevel + 300x362 content parent
+        // 0x10000180 + 5px = 310x372, verified by PanelHost_
+        // AuthorsFixedWidthAndBottomOnlyResizeContract). Its authored
+        // 0x3C..0x3F values already include that bevel. Without
+        // DatConstraintSourceIsOuterFrame, RetailWindowFrame.ResolveConstraint
+        // added the wrapper's OWN 10px chrome inset on top — double-counting
+        // the bevel and clamping the mounted window's MinWidth to 320 while
+        // its actual outer width stayed 310, silently below its own minimum.
         ElementInfo? hostConstraint;
         lock (_bindings.Assets.DatLock)
             hostConstraint = LayoutImporter.ImportInfos(
@@ -4137,11 +4148,25 @@ public sealed class RetailUiRuntime : IDisposable
                 Chrome = RetailWindowChrome.NineSlice,
                 Left = 540f,
                 Top = 18f,
+                // CT6 fix round (2026-08-25, S4 ruling): mount at retail's
+                // authored DEFAULT — the host's own content parent
+                // (0x10000180) is 300x362, not 0x2100002E's own 300x600
+                // authoring canvas (which retail scroll-clips into that
+                // slot). 362 + the 10px NineSlice inset = 372, exactly the
+                // host's own authored MinHeight — matching the ground-truth
+                // finding that retail's Character/Skills window opens AT its
+                // resize floor and can only be dragged taller. The 9
+                // attribute/vital rows (180px) overflow the resulting 160px
+                // list at this default; that is retail-correct, not a bug —
+                // the list's own scrollbar (0x1000023E, hide-when-disabled)
+                // activates immediately.
+                ContentHeight = 362f,
                 ResizeX = false,
                 ResizeY = true,
                 ResizableEdges = ResizeEdges.Bottom,
                 ConstrainResizeToParent = true,
                 DatConstraintSource = hostConstraint,
+                DatConstraintSourceIsOuterFrame = true,
                 Visible = false,
                 ContentAnchors = AnchorEdges.Left | AnchorEdges.Top | AnchorEdges.Bottom,
                 ContentClickThrough = false,