feat(chat): retail text style — two-plane glyph outlines, authored SpewBox/chat styles

Campaign CH round 4, user-gate items 1+2. Root cause: retail ships a
second (background) glyph atlas per font, dilated 2px on every side,
plus two border-pixel scalars (Font.NumHorizontalBorderPixels/
NumVerticalBorderPixels) that acdream's font reader never read — so
even the pre-existing outline parameter drew almost nothing once
enabled. Landed together (either half alone is a no-op or a
regression):

- UiDatFont carries BorderX/BorderY from the DAT font resource.
- UiRenderContext.DrawStringDat inflates the background blit's source
  and destination rect by that margin and restructures into retail's
  exact two-pass whole-string outline-then-fill model
  (UIElement_Text::DrawSelf), plus the 8-neighbour +-1px fallback for
  fonts with no background atlas. Corrects the stale "property 0xd"
  comment to the real ids, 0x21 (Outline) / 0x22 (OutlineColor).
- LayoutDesc property 0x21/0x22 import (ElementInfo.Outline/
  OutlineColor, LayoutImporter.ReadState, ElementReader.Merge/
  ApplyCanonicalLegacyProjection, DatWidgetFactory.BuildText) so every
  authored-outline element across the DAT set is correct at once.
- SpewBox: RetailFontId corrected from a round-3 heuristic
  (0x40000025) to the actually-authored 0x40000001 (18px bold serif),
  Outline=true set on the controller's UiText. Fill colour stays the
  user-gate-round-1-pinned yellow — font atlases are alpha-only
  (PFID_A8), so there is no baked shading that could explain the
  screenshot's gold as anything other than the outline itself.
- Chat transcript: default fill now seeds from its authored
  ARGB(255,204,204,204) instead of an unrelated color-table slot
  (ChatTranscriptRenderer.BuildLines takes the transcript's own
  DefaultColor as a parameter); the 34-entry LogTextType table is
  untouched, and every existing CH1 conformance test stays green
  unmodified.

Regenerated the committed chat_2100006f.json fixture from the real
installed DAT, confirming end to end (not by missing-field default)
that the transcript carries no outline.

Tests: font-reader border fields + inflation math pinned against the
real DAT font, two-pass draw ordering/tint/inflation via a new
TextRenderer.DebugSpriteSegmentVerts test seam, property 0x21/0x22
import at both the ElementReader.Merge and StateDesc-property layers,
SpewBox font/outline, and the chat default-shade seed with the color
table proven untouched.

Full Release suite: 12,610 passed / 4 skipped / 0 failed
(AcDream.slnx, complete solution).

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

src/AcDream.App/UI/Layout/ChatTranscriptRenderer.cs

@@ -45,22 +45,43 @@ internal static class ChatTranscriptRenderer
     /// advancing for lines actually appended to THIS window's own scroll
     /// (<c>AppendStringInfoWithFont</c> only runs for displayed lines).
     /// </param>
+    /// <param name="defaultColor">
+    /// The transcript element's own base fill color — retail's
+    /// <c>m_curFontColor</c> BEFORE any <c>AppendTextWithFont</c> call ever
+    /// tints it, i.e. the value <c>DoFontReset</c> seeds from the element's
+    /// authored LayoutDesc property <c>0x1B</c> (style <c>0x10000372</c>:
+    /// <c>ARGB(255,204,204,204)</c> for the main chat transcript). Campaign
+    /// CH round 4 (<c>docs/research/2026-08-10-retail-ui-text-style.md</c>
+    /// §5.2 Fix 5): this used to be hardcoded to
+    /// <c>RetailChatColorTable.TryGetColor(0x00u, ...)</c> (colorGreen) —
+    /// the color table's OWN default-slot color, not the ELEMENT's authored
+    /// default. The two are unrelated: the table governs the per-message
+    /// <c>LogTextType</c> tint (untouched by this parameter — every message
+    /// with an in-range type still resolves its own table color exactly as
+    /// before), while <paramref name="defaultColor"/> is only the carried-
+    /// forward seed for a line whose type falls OUTSIDE the table's 34
+    /// entries (matching retail's out-of-range "leave <c>m_curFontColor</c>
+    /// unchanged" rule — see <see cref="RetailChatColorTable"/>'s own doc).
+    /// Callers pass their transcript's <see cref="UiText.DefaultColor"/>.
+    /// </param>
     public static List<UiText.Line> BuildLines(
         IReadOnlyList<FormattedLine> detailed,
         float maxW,
         Func<string, float> measure,
-        Func<uint, bool>? accept)
+        Func<uint, bool>? accept,
+        Vector4 defaultColor)
     {
         var result = new List<UiText.Line>(detailed.Count);
         if (detailed.Count == 0)
             return result;
 
-        // Retail's font-color state (m_curFontColor) persists across every
-        // line actually appended to this window — an out-of-range LogTextType
-        // leaves it unchanged rather than reverting to a default (color-table
-        // doc §3.2). Seed the carry with retail's own unfilled-slot default
-        // (colorGreen, index 0x00).
-        RetailChatColorTable.TryGetColor(0x00u, out Vector4 currentColor);
+        // Retail's font-color state (m_curFontColor) persists across every line
+        // actually appended to this window — an out-of-range LogTextType leaves it
+        // unchanged rather than reverting to a color-table default (color-table doc
+        // §3.2). Seed the carry with the ELEMENT's own authored default fill
+        // (defaultColor), matching retail's DoFontReset — not the color table's
+        // unrelated index-0x00 slot.
+        Vector4 currentColor = defaultColor;
         foreach (FormattedLine d in detailed)
         {
             if (accept is not null && !accept(d.LogTextType))