docs(D.2b): register AP-32 + IA-15 amend for importer; doc/test review fixes (N1/N4)

Process/quality items from the LayoutDesc-importer final review — no runtime
behavior change.

I1a — amend IA-15: the 8-piece chrome edge/corner→position mapping is no longer
a guess.  The LayoutImporter (ACDREAM_RETAIL_UI_IMPORTER) reads real LayoutDesc
dat data and resolves positions + sprite ids directly; locked by the conformance
fixture vitals_2100006C.json.  Residual risk trimmed to anchor resolution at
non-800×600 + controls.ini cascade.  Pointers added to LayoutImporter.cs and the
format-doc.

I1b — add AP-32: the importer collapses the dat's nested meter structure
(Type-7 → two Type-3 containers → three image-slice grandchildren each) into
UiMeter's programmatic 3-slice fields instead of building those nodes generically
and porting UIElement_Meter::DrawChildren.  Standalone Type-0 text elements are
also skipped (Plan 2).  Retail oracles: UIElement_Meter::DrawChildren @0x46fbd0,
UIElement_Text::DrawSelf @0x467aa0.

I1c — AP section header 31 → 32.

N1 — ElementReader.cs: comment at the Type-merge line explaining that a derived
Type 0 (text element) inherits the base's Type 12 (style prototype), which
DatWidgetFactory skips; safe for Plan 1 because vitals numbers render via
UiMeter.Label.  Format-doc §10: correct the "render as UiDatElement" sentence to
"skipped entirely" (Type-0 → inherits Type-12 via Merge → factory returns null).

N4 — new conformance test VitalsTree_TextLabel_InheritsFontDidFromBaseLayout:
walks the raw ElementInfo tree from the fixture and asserts at least one element
carries FontDid==0x40000000, proving Resolve()'s inheritance merge fired against
real dat data.  FixtureLoader gains LoadVitalsInfos() that returns the raw tree
without calling Build.

Tests: 36 pass (was 35), 0 errors, 0 warnings.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/AcDream.App.Tests/UI/Layout/FixtureLoader.cs

@@ -24,6 +24,19 @@ public static class FixtureLoader
     /// dat font — sufficient for conformance checks on tree structure and slice ids.
     /// </summary>
     public static ImportedLayout LoadVitals()
+    {
+        var root = LoadVitalsInfos();
+        return LayoutImporter.Build(root, _ => (0u, 0, 0), null);
+    }
+
+    /// <summary>
+    /// Deserializes the committed <c>vitals_2100006C.json</c> fixture into a raw
+    /// <see cref="ElementInfo"/> tree WITHOUT calling <see cref="LayoutImporter.Build"/>.
+    /// Use this when the test needs to inspect the resolved <see cref="ElementInfo"/>
+    /// tree directly (e.g. inheritance-resolution checks) without exercising the
+    /// widget factory.
+    /// </summary>
+    public static AcDream.App.UI.Layout.ElementInfo LoadVitalsInfos()
     {
         var fixturePath = Path.Combine(AppContext.BaseDirectory, "UI", "Layout", "fixtures", "vitals_2100006C.json");
         if (!File.Exists(fixturePath))
@@ -35,9 +48,7 @@ public static class FixtureLoader
         ReadOnlySpan<byte> span = bytes;
         if (span.Length >= 3 && span[0] == 0xEF && span[1] == 0xBB && span[2] == 0xBF)
             span = span[3..];
-        var root = JsonSerializer.Deserialize<AcDream.App.UI.Layout.ElementInfo>(span, _opts)
+        return JsonSerializer.Deserialize<AcDream.App.UI.Layout.ElementInfo>(span, _opts)
             ?? throw new InvalidOperationException($"fixture deserialized to null: {fixturePath}");
-
-        return LayoutImporter.Build(root, _ => (0u, 0, 0), null);
     }
 }

tests/AcDream.App.Tests/UI/Layout/LayoutConformanceTests.cs

@@ -93,4 +93,49 @@ public class LayoutConformanceTests
         var (file, _) = datElem.ActiveMedia();
         Assert.Equal(0x060074C3u, file);
     }
+
+    // ── Test 4 (N4): Inheritance resolution — FontDid propagated from base ───
+
+    /// <summary>
+    /// Proves that <c>Resolve()</c>'s inheritance merge fired against real dat data:
+    /// at least one element in the fixture tree must have <c>FontDid == 0x40000000</c>
+    /// (the vitals font), inherited from the base-layout prototype <c>0x10000376</c>
+    /// in <c>0x2100003F</c> via the <c>BaseElement</c> / <c>BaseLayoutId</c> chain.
+    ///
+    /// <para>
+    /// The three text labels (<c>0x100000EB</c> health, <c>0x100000ED</c> stamina,
+    /// <c>0x100000EF</c> mana) are Type=0 derived elements with no own font property.
+    /// The base element <c>0x10000376</c> carries <c>Properties[0x1A]</c> →
+    /// <c>ArrayBaseProperty[ DataIdBaseProperty{Value=0x40000000} ]</c>.
+    /// <see cref="ElementReader.Merge"/> propagates this via the "FontDid: derived wins
+    /// if non-zero, otherwise inherit" rule.
+    /// </para>
+    ///
+    /// <para>
+    /// This test verifies end-to-end inheritance resolution against the committed fixture
+    /// (format doc §10, <c>docs/research/2026-06-15-layoutdesc-format.md</c>).
+    /// It operates on the raw <see cref="ElementInfo"/> tree, NOT the widget tree,
+    /// so the factory dispatch (Type 12 → skip) does not interfere.
+    /// </para>
+    /// </summary>
+    [Fact]
+    public void VitalsTree_TextLabel_InheritsFontDidFromBaseLayout()
+    {
+        var root = FixtureLoader.LoadVitalsInfos();
+
+        // Walk the full ElementInfo tree and collect all FontDid values.
+        var fontDids = new System.Collections.Generic.List<uint>();
+        CollectFontDids(root, fontDids);
+
+        // At least one element must carry FontDid == 0x40000000 (the vitals font).
+        // In practice, the three text labels (health/stamina/mana) all inherit it.
+        Assert.Contains(0x40000000u, fontDids);
+    }
+
+    private static void CollectFontDids(ElementInfo node, System.Collections.Generic.List<uint> acc)
+    {
+        if (node.FontDid != 0) acc.Add(node.FontDid);
+        foreach (var child in node.Children)
+            CollectFontDids(child, acc);
+    }
 }