fix #430: tooltip wrap and draw honor the text child's authored margins

Third owner-screenshot round: acdream fit one more word per line than
retail and drew glyphs flush against the popup's right border. Retail's
InqSizewMargins @0x00469660 wraps the glyph list at
(bound - m_margL - m_margR) and adds the margins back into the measured
width; the popup skins' shared text child 0x10000396 authors margins
L=2/R=2 (U=2/D=2 on three of the four skins — live-DAT probed). The
presenter now subtracts the horizontal margins from both wrap passes,
re-adds them into the measured width used for root sizing, and counts
the vertical margins in the measured/re-wrapped heights; the widget's
own draw already insets by all four margins (UiText ContentOffsetX +
the top/bottom inset), so the right-side spacing returns for free.

TooltipSkinLiveDatTests pins the authored margins per skin alongside
the P0x3D=256 wrap bound; a new presenter test proves margins shrink
the wrap bound and survive onto the widget.

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

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

@@ -29,16 +29,26 @@ public sealed class TooltipSkinLiveDatTests
         Assert.NotNull(tree);
 
         int textChildren = 0;
-        void Walk(ElementInfo e)
+        void Walk(ElementInfo e, uint parentId)
         {
             if (e.Id == 0x10000396u && e.Type == 12)
             {
                 textChildren++;
                 Assert.Equal(256, e.MaxWidth);
+                // Retail wraps at (256 - margL - margR) and draws inset by
+                // the margins — the CA5 owner-screenshot delta (one extra
+                // word on line one + text flush against the right border).
+                // All four skins author L=2/R=2; skin 0x10000398 alone
+                // authors no vertical margins (live-DAT probe 2026-08-24).
+                Assert.Equal(2, e.MarginLeft);
+                Assert.Equal(2, e.MarginRight);
+                int vertical = parentId == 0x10000398u ? 0 : 2;
+                Assert.Equal(vertical, e.MarginTop);
+                Assert.Equal(vertical, e.MarginBottom);
             }
-            foreach (var c in e.Children) Walk(c);
+            foreach (var c in e.Children) Walk(c, e.Id);
         }
-        Walk(tree!);
+        Walk(tree!, 0);
         Assert.True(textChildren >= 4,
             $"expected the text child under all four popup skins, found {textChildren}");
     }