fix #416 #415: the retail button state/media machine — roster hover highlight clears; probe wait verbs bind without an artifact dir

#416 (char-select roster highlight never cleared on hover-leave): three
decomp-grounded mechanisms replace the media-keyed _availableStates
approximation.
- UIElement_Button::UpdateState_ @0x00471CF0: the button machine commits
  ONLY states authored on the button's OWN ElementDesc (AccessStateDesc
  gate); unauthored requests no-op, preserving custom semantic states.
- UIElement::SetState @0x00464E70: an unauthored state id is coerced to
  state 0 (the unnamed base state) and committed — ported into
  UiDatElement.TrySetRetailState with the base-descriptor PassToChildren
  cascade arm.
- The SetState media rule @0x004651c0: a committed state replaces the
  playing media ONLY when its media array is non-empty. UiButton now keeps
  per-face-segment media states under that rule (segments model retail's
  PassToChildren children), and LayoutImporter records the raw MediaCount
  including the File=0 draw-nothing images the drawable filter drops —
  the roster bar children's base state is exactly such an image, and it is
  what clears the bar.
The row template truth (probe, installed DAT): the row authors EMPTY
Normal/rollover/Highlight descriptors with PassToChildren; the three bar
children author rollover/Highlight media, NO Normal state, and a File=0
base image. An empty-media Normal_pressed still never blanks a Normal-art
button (the media rule keeps the previous art — the exact behavior the
old gate approximated), and the Appearance spins' property-only Highlight
now genuinely commits: label recolors, arrow art lingers — the retail
split AP-222 approximated with a requested-keyed label hack, now retired.
Live-verified at char select: hover +alex shows the grey bar, moving off
clears it, the selected row keeps its amber bar.

#415 (probe wait world-* verbs dead): the filed snapshot-reset diagnosis
was wrong — the automation bridge simply never bound without
ACDREAM_AUTOMATION_ARTIFACT_DIR. A facts-only
WorldRevealFactsAutomationRuntime now binds whenever the retained UI
exists; checkpoint/screenshot verbs still require the artifact directory
and now report that instead of a generic timeout.

App tests 5568/3 skips, Runtime 1756/0, UI.Abstractions 926/0.

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

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

@@ -603,6 +603,10 @@ public static class LayoutImporter
             Name = name,
             PassToChildren = sd.PassToChildren,
             IncorporationFlags = (uint)sd.IncorporationFlags,
+            // Raw media presence, INCLUDING File=0 draw-nothing images the
+            // image filter below drops — retail's SetState media-machine
+            // reset gates on m_media.m_num != 0 (#416; see UiStateInfo).
+            MediaCount = sd.Media.Count,
         };
 
         bool imageRead = false;

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

@@ -103,7 +103,33 @@ public class UiDatElement : UiElement, IUiDatStateful
             if (string.IsNullOrEmpty(stateName))
                 stateName = RetailUiStateIds.StateName(stateId);
             if (string.IsNullOrEmpty(stateName) || !Info.StateMedia.ContainsKey(stateName))
-                return false;
+            {
+                // Retail UIElement::SetState @0x00464E70: AccessStateDesc on an
+                // UNAUTHORED state id coerces the request to STATE 0 — the
+                // unnamed base state — and commits it (m_state/m_curStateDesc
+                // are written unconditionally), so the previous state's media
+                // can never linger. The old refusal here latched state media
+                // forever (#416): the character-select roster row's highlight
+                // bar children (0x10000481/82/83 in 0x21000004) author
+                // Normal_rollover/Highlight media but NO 'Normal' state at
+                // all, so the row's PassToChildren 'Normal' hover-leave
+                // cascade landed here and the bars never cleared. Retail's
+                // state-0 arm cascades state 0 to children off the BASE
+                // descriptor's own PassToChildren (m_desc.m_bPassToChildren,
+                // @0x00464eca), and the per-state Invisible honor below stays
+                // scoped to NAMED authored states exactly as before (the #408
+                // gate) — selectedState remains null on this path.
+                ActiveState = "";
+                if (Info.States.TryGetValue(
+                        UiStateInfo.DirectStateId, out UiStateInfo? baseState)
+                    && baseState.PassToChildren)
+                {
+                    foreach (UiElement child in Children)
+                        if (child is IUiDatStateful stateful)
+                            stateful.TrySetRetailState(UiStateInfo.DirectStateId);
+                }
+                return true;
+            }
             ActiveState = stateName;
         }
 

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

@@ -126,6 +126,18 @@ public sealed class UiStateInfo
     public UiCursorMedia? Cursor;
     public UiPropertyBag Properties = new();
 
+    /// <summary>
+    /// Raw authored MediaDesc count for this state, INCLUDING File=0
+    /// draw-nothing images that <see cref="Image"/>/StateMedia deliberately
+    /// drop. Retail's <c>UIElement::SetState @0x00464E70</c> tail resets the
+    /// media machine only when the committed state's media array is
+    /// NON-EMPTY (<c>m_media.m_num != 0</c> gate @0x004651c0) — an authored
+    /// state with an empty media array keeps the PREVIOUS media playing,
+    /// while an authored File=0 image counts as media and clears the face
+    /// (#416).
+    /// </summary>
+    public int MediaCount;
+
     public UiStateInfo Clone()
         => new()
         {
@@ -136,6 +148,7 @@ public sealed class UiStateInfo
             Image = Image,
             Cursor = Cursor,
             Properties = Properties.Clone(),
+            MediaCount = MediaCount,
         };
 
     public static UiStateInfo Merge(UiStateInfo baseState, UiStateInfo derivedState)
@@ -148,5 +161,11 @@ public sealed class UiStateInfo
             Image = derivedState.Image ?? baseState.Image,
             Cursor = derivedState.Cursor ?? baseState.Cursor,
             Properties = UiPropertyBag.Merge(baseState.Properties, derivedState.Properties),
+            // Media arrays do not merge entry-wise in retail (a derived
+            // StateDesc replaces the base one); the derived count wins when
+            // the derived state authors ANY media, else the base's carries.
+            MediaCount = derivedState.MediaCount != 0
+                ? derivedState.MediaCount
+                : baseState.MediaCount,
         };
 }