fix(ui): OP2 re-review closure (coordinator pass) — AP-195, tooltip port, zero-children pin

Closes the mechanism lens's REOPEN (one MUST-FIX) and both lenses' small
residuals on the OP2 rework (b236a442); the blast lens re-review was
CLOSED outright. Fable-direct per the two-failure escalation rule.

- AP-195 filed: UIOption_CheckboxBitfield64 ports HALF of Refresh
  @0x004859C0 — the ANY-set checkbox predicate is exact, but the ALL-set
  LED media swap (P0x10000082=0x06004D17 / P0x10000083=0x06004D19) and
  the ListBox self-sizing tail (ResizeTo/CalculatePaperSize — the block
  IS a UIElement_ListBox in retail) are unported, and the block's row
  stacking is a second divergent implementation beside UiTemplateListBox.
  All due at OP5 before the Chat tab's connected gate; the IsSet doc
  comment now names both halves instead of quoting only the ported one.
- Row tooltips: UiButton gains settable TooltipText surfaced through the
  shared GetTooltipText hover pipeline (UiCatalogSlot's pattern);
  UiCheckboxBitfield64.AddChild applies the row tooltip retail stamps in
  CreateChildren @0x00485DF0, and documents that the 0x10000084 row-index
  attribute stamp is deliberately replaced by the typed mask closure.
- AD-73 addendum: UiTemplateListBox.ConsumesDatChildren=true is inert
  only while no authored Type-5 element carries children — that premise
  is now conformance-PINNED across all 32 fixtures (a future DAT
  regeneration surfacing an authored child fails the build instead of
  silently dropping it).
- Plan doc: OP2's contract names UiTabPanel.cs (retail UIElement_Panel),
  not the fictional-class-named UiTabControl.cs; ledger records OP1 and
  OP2 both CLOSED.

Full Release suite: 12,871 passed / 4 skipped / 0 failed.

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

tests/AcDream.App.Tests/UI/Layout/OP2ReworkBlastRadiusConformanceTests.cs

@@ -1,3 +1,5 @@
+using System.IO;
+using System.Text.Json;
 using AcDream.App.UI;
 using AcDream.App.UI.Layout;
 
@@ -154,4 +156,51 @@ public class OP2ReworkBlastRadiusConformanceTests
         Assert.Equal(0, host.ContentHeight);
         Assert.True(host.ClickThrough);
     }
+
+    /// <summary>
+    /// AD-73 addendum (OP2 re-review closure, 2026-08-11):
+    /// <see cref="UiTemplateListBox.ConsumesDatChildren"/> is <c>true</c> where the
+    /// pre-rework generic fallback's was not. That delta drops nothing ONLY while no
+    /// authored Type-5 element carries children — a premise the re-review verified by
+    /// hand across all 32 fixtures. This test turns that manual sweep into a build
+    /// gate: if a future DAT regeneration surfaces a Type-5 element WITH authored
+    /// children, this fails loudly instead of the children silently vanishing.
+    /// </summary>
+    [Fact]
+    public void EveryAuthoredType5Element_HasZeroChildren_AcrossAllFixtures()
+    {
+        string fixturesDir = Path.Combine(
+            AppContext.BaseDirectory, "UI", "Layout", "fixtures");
+        string[] fixtures = Directory.GetFiles(fixturesDir, "*.json");
+        Assert.NotEmpty(fixtures);
+
+        var opts = new JsonSerializerOptions { IncludeFields = true };
+        int type5Seen = 0;
+        foreach (string file in fixtures)
+        {
+            var root = JsonSerializer.Deserialize<ElementInfo>(
+                File.ReadAllText(file), opts);
+            Assert.NotNull(root);
+            Walk(root!, file);
+        }
+
+        // The premise is only meaningful if the sweep actually saw Type-5
+        // elements (16 across the current fixture set).
+        Assert.True(type5Seen >= 10, $"sweep saw only {type5Seen} Type-5 elements");
+
+        void Walk(ElementInfo node, string file)
+        {
+            if (node.Type == 5u)
+            {
+                type5Seen++;
+                Assert.True(
+                    node.Children.Count == 0,
+                    $"{Path.GetFileName(file)}: Type-5 element 0x{node.Id:X8} authors "
+                    + $"{node.Children.Count} children — UiTemplateListBox.ConsumesDatChildren "
+                    + "would drop them; see AD-73's addendum.");
+            }
+            foreach (ElementInfo child in node.Children)
+                Walk(child, file);
+        }
+    }
 }