feat(D.2b): DatWidgetFactory — Type→widget hybrid + meter slice extraction

Hybrid factory mapping ElementInfo.Type to a behavioral widget or the
UiDatElement generic fallback.  Type 7 (UIElement_Meter) → UiMeter with
back/front 3-slice ids populated from grandchild image elements; Type 12
(style prototypes / BaseElement stores) → null so the importer skips
them; all other types → UiDatElement.  Rect + anchors are set on every
returned widget via ElementReader.ToAnchors.

BuildMeter walks two levels of the element tree: the two Type-3 slice
containers ordered by ReadOrder (back behind, front on top), then within
each container the image children that carry a DirectState ("" key)
ordered by X for left-cap/center-tile/right-cap.  The expand-detail
overlay (present in the front container with only named ShowDetail/
HideDetail states and no "" entry) is excluded by the TryGetValue("")
filter automatically — no name-matching needed.

Fill/Label providers are intentionally NOT set here; Task 6
(VitalsController) binds them to live stat data.

5 TDD tests: Type7→UiMeter, UnknownType→UiDatElement, Type12→null,
rect+anchors propagation, and meter slice extraction with overlay exclusion.

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

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

@@ -0,0 +1,112 @@
+using AcDream.App.UI;
+using AcDream.App.UI.Layout;
+namespace AcDream.App.Tests.UI.Layout;
+
+public class DatWidgetFactoryTests
+{
+    private static (uint, int, int) NoTex(uint _) => (0, 0, 0);
+
+    // ── Test 1: Type 7 → UiMeter ─────────────────────────────────────────────
+
+    [Fact]
+    public void Type7_Meter_MakesUiMeter()
+    {
+        var e = DatWidgetFactory.Create(new ElementInfo { Type = 7, Width = 150, Height = 16 }, NoTex, null);
+        Assert.IsType<UiMeter>(e);
+    }
+
+    // ── Test 2: Unknown type → UiDatElement fallback ─────────────────────────
+
+    [Fact]
+    public void UnknownType_FallsBackToGeneric()
+    {
+        var e = DatWidgetFactory.Create(new ElementInfo { Type = 999 }, NoTex, null);
+        Assert.IsType<UiDatElement>(e);
+    }
+
+    // ── Test 3: Type 12 → null (style prototype, never rendered) ─────────────
+
+    [Fact]
+    public void Type12_StylePrototype_ReturnsNull()
+    {
+        var e = DatWidgetFactory.Create(new ElementInfo { Type = 12 }, NoTex, null);
+        Assert.Null(e);
+    }
+
+    // ── Test 4: Rect + anchors set from ElementInfo ───────────────────────────
+
+    /// <summary>
+    /// A Type-3 element with X=5,Y=21,W=150,H=16, Left=1,Top=1,Right=2 should have
+    /// its rect + anchors copied onto the returned widget.
+    /// Left=1 (near-pin → AnchorEdges.Left), Top=1 (near-pin → AnchorEdges.Top),
+    /// Right=2 (far-pin → AnchorEdges.Right), Bottom=0 (no anchor → neither).
+    /// Combined: Left | Top | Right.
+    /// </summary>
+    [Fact]
+    public void RectAndAnchors_SetFromElementInfo()
+    {
+        var info = new ElementInfo
+        {
+            Type   = 3,
+            X      = 5,   Y      = 21,
+            Width  = 150, Height = 16,
+            Left   = 1,   Top    = 1,
+            Right  = 2,   Bottom = 0,
+        };
+        var e = DatWidgetFactory.Create(info, NoTex, null)!;
+        Assert.Equal(5f,   e.Left);
+        Assert.Equal(21f,  e.Top);
+        Assert.Equal(150f, e.Width);
+        Assert.Equal(16f,  e.Height);
+        Assert.Equal(AnchorEdges.Left | AnchorEdges.Top | AnchorEdges.Right, e.Anchors);
+    }
+
+    // ── Test 5: Meter slice extraction (the important one) ───────────────────
+
+    /// <summary>
+    /// A meter (Type 7) whose two Type-3 containers each carry 3 image children
+    /// (ordered by X, bearing a DirectState "" sprite), plus the front container
+    /// has a fourth expand-overlay child with ONLY a named "ShowDetail" state —
+    /// that overlay must be excluded from the slice count.
+    /// </summary>
+    [Fact]
+    public void MeterSliceExtraction_ReadsGrandchildImageIds_IgnoresOverlay()
+    {
+        // Slice ids sourced from format doc §11 — real health-bar ids.
+        const uint BackL = 0x0600747Eu, BackT = 0x0600747Fu, BackR = 0x06007480u;
+        const uint FrontL = 0x06007481u, FrontT = 0x06007482u, FrontR = 0x06007483u;
+        const uint OverlayFile = 0x06007490u;
+
+        // Back container (ReadOrder 0 — drawn first / behind)
+        var backChild = new ElementInfo { Type = 3, ReadOrder = 0 };
+        backChild.Children.Add(new ElementInfo { X = 0,   StateMedia = { [""] = (BackL,  1) } });
+        backChild.Children.Add(new ElementInfo { X = 10,  StateMedia = { [""] = (BackT,  1) } });
+        backChild.Children.Add(new ElementInfo { X = 140, StateMedia = { [""] = (BackR,  1) } });
+
+        // Front container (ReadOrder 1 — drawn on top)
+        var frontChild = new ElementInfo { Type = 3, ReadOrder = 1 };
+        frontChild.Children.Add(new ElementInfo { X = 0,   StateMedia = { [""] = (FrontL, 1) } });
+        frontChild.Children.Add(new ElementInfo { X = 10,  StateMedia = { [""] = (FrontT, 1) } });
+        frontChild.Children.Add(new ElementInfo { X = 140, StateMedia = { [""] = (FrontR, 1) } });
+        // Expand-detail overlay: named state only — NO DirectState "" — must be ignored.
+        frontChild.Children.Add(new ElementInfo
+        {
+            X = 0,
+            StateMedia = { ["ShowDetail"] = (OverlayFile, 3) }
+        });
+
+        var meter = new ElementInfo { Type = 7, Width = 150, Height = 16 };
+        meter.Children.Add(backChild);
+        meter.Children.Add(frontChild);
+
+        var e = DatWidgetFactory.Create(meter, NoTex, null);
+
+        var m = Assert.IsType<UiMeter>(e);
+        Assert.Equal(BackL,  m.BackLeft);
+        Assert.Equal(BackT,  m.BackTile);
+        Assert.Equal(BackR,  m.BackRight);
+        Assert.Equal(FrontL, m.FrontLeft);
+        Assert.Equal(FrontT, m.FrontTile);
+        Assert.Equal(FrontR, m.FrontRight);
+    }
+}