fix(D.5.1): toolbar movable + chrome-grab + peace-only indicator + no prototype square

D1 — Toolbar not movable: toolbarRoot.Anchors = AnchorEdges.None (was Left|Top)
so ApplyAnchor early-returns and doesn't re-pin the window every frame.
Matches the vitalsRoot idiom exactly.

D2 — Cannot grab toolbar by chrome: toolbarRoot.ClickThrough = false
so HitTest succeeds over the UiDatElement chrome and the drag starts.
UiDatElement ctor defaults ClickThrough=true; vitalsRoot already overrides it.

C1 — All four combat-mode indicators visible at once (war/flame stacked on
peace): ports gmToolbarUI::RecvNotice_SetCombatMode
(acclient_2013_pseudo_c.txt:196632-196669). CombatIndicatorIds[] maps
index 0-3 to NonCombat/Melee/Missile/Magic; SetCombatMode shows exactly one
and hides the other three. Default to NonCombat at bind (player always
spawns in peace). Wires CombatState.CombatModeChanged for live updates.
Tests: CombatIndicator_defaultNonCombat_onlyPeaceVisible,
CombatIndicator_setCombatModeMelee_onlyMeleeVisible,
CombatIndicator_liveSignal_updatesWhenCombatStateChanges.

V1 — Blue empty-slot square at top-left (prototype 0x100001B2 materialized):
ImportInfos now skips top-level elements that are (a) referenced as a
BaseElement by another element in the same layout AND (b) have no own state
media. The CollectBaseRefsInDesc walk covers nested children; HasNoOwnMedia
re-uses ToInfo's media extraction. The Resolve path reads BaseElement from the
raw dat via dats.Get<LayoutDesc> — it never depends on the prototype being in
the built widget tree — so the skip is safe. Conformance tests (vitals, chat)
are unaffected (they exercise Build, not ImportInfos).
Test: BuildFromInfos_PrototypeSkipped_DerivedPresent_PrototypeAbsent.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

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

@@ -139,9 +139,34 @@ public static class LayoutImporter
         var ld = dats.Get<LayoutDesc>(layoutId);
         if (ld is null) return null;
 
+        // Collect the set of element ids that are referenced as a BaseElement by ANY
+        // element in THIS layout (where BaseLayoutId == layoutId). Such elements are
+        // purely inheritance templates ("prototypes") — retail never instantiates them
+        // as live widgets. Example: the toolbar slot prototype 0x100001B2 in LayoutDesc
+        // 0x21000016, which all 18 slot elements inherit from and which has no own media.
+        //
+        // NOTE: the Resolve path reads BaseElement from the raw dat directly (via
+        // dats.Get<LayoutDesc>), so the prototype never needs to appear in the built
+        // widget tree for inheritance to work. Skipping it here is safe.
+        var referencedAsBase = new HashSet<uint>();
+        foreach (var kv in ld.Elements)
+            CollectBaseRefsInDesc(kv.Value, layoutId, referencedAsBase);
+
         var tops = new List<ElementInfo>();
         foreach (var kv in ld.Elements)
-            tops.Add(Resolve(dats, kv.Value, new HashSet<(uint, uint)>()));
+        {
+            // Skip pure prototype elements: top-level elements that are referenced as a
+            // base template by another element in this same layout AND have no own state
+            // media (so they draw nothing and contribute nothing but their inherited shape).
+            var d = kv.Value;
+            if (referencedAsBase.Contains(d.ElementId) && HasNoOwnMedia(d))
+            {
+                Console.WriteLine($"[D.2b] LayoutImporter: skipping prototype element 0x{d.ElementId:X8} in layout 0x{layoutId:X8} (no own media, referenced as BaseElement).");
+                continue;
+            }
+
+            tops.Add(Resolve(dats, d, new HashSet<(uint, uint)>()));
+        }
 
         return tops.Count == 1
             ? tops[0]
@@ -270,6 +295,37 @@ public static class LayoutImporter
         }
     }
 
+    // ── Prototype detection helpers ───────────────────────────────────────────
+
+    /// <summary>
+    /// Recursively walks <paramref name="d"/> and all its children, adding to
+    /// <paramref name="result"/> the <c>BaseElement</c> of every descriptor that
+    /// references this layout (<c>BaseLayoutId == layoutId</c>). Used by
+    /// <see cref="ImportInfos"/> to identify pure prototype/template elements that
+    /// should not be instantiated as live widgets.
+    /// </summary>
+    private static void CollectBaseRefsInDesc(ElementDesc d, uint layoutId, HashSet<uint> result)
+    {
+        if (d.BaseElement != 0 && d.BaseLayoutId == layoutId)
+            result.Add(d.BaseElement);
+        foreach (var kv in d.Children)
+            CollectBaseRefsInDesc(kv.Value, layoutId, result);
+    }
+
+    /// <summary>
+    /// Returns true when <paramref name="d"/> carries no own state media — i.e. its
+    /// <c>StateDesc</c> (DirectState) and <c>States</c> (named states) yield no
+    /// <see cref="MediaDescImage"/> entries with a non-zero file id.
+    /// Such elements are pure inheritance templates with no rendering content.
+    /// </summary>
+    private static bool HasNoOwnMedia(ElementDesc d)
+    {
+        // Re-use ToInfo's media extraction: if the resulting StateMedia is empty the
+        // element has no renderable image in any state.
+        var info = ToInfo(d);
+        return info.StateMedia.Count == 0;
+    }
+
     // ── Element tree search ───────────────────────────────────────────────────
 
     /// <summary>