fix(D.5.3a): selected-object meter visual-gate fixes (name, gate, flash, magenta)

Visual gate against retail surfaced several fidelity gaps in the selected-object
strip; all fixed and user-confirmed. Faithful to gmToolbarUI::HandleSelectionChanged
(acclient_2013_pseudo_c.txt:198635) + RecvNotice_UpdateObjectHealth (:196213).

- UiMeter.DrawHBar: guard each slice on `id != 0` BEFORE resolve. resolve(0)
  returns the 1x1 magenta placeholder with a non-zero GL handle, so the single-
  image meter (caps id=0) was drawing 1px magenta caps at the bar's ends. The
  3-slice vitals meter (all ids set) was unaffected. (the magenta-lines bug)
- SelectedObjectController: meter visibility is now UpdateHealth-driven (shown when
  health is known for the selected guid — HasHealth at select or HealthChanged),
  not shown-on-select; brief green selection flash via Tick revert; overlay floated
  above the meter so the flash isn't hidden by the bar; name top-aligned into the
  bar sprite's black band (NameBandHeight) with the bar below.
- GameWindow.IsHealthBarTarget: gate the health bar on the server PWD bits
  BF_ATTACKABLE (0x10) | BF_PLAYER (0x8) — friendly/vendor NPCs and attackable
  Doors (Misc type) are name-only; players/monsters get the bar. Replaces the
  too-loose IsLiveCreatureTarget. Wired SelectedObjectController.Tick in OnUpdate.
- CombatState.HasHealth(guid): distinguishes a known health value from the 1.0
  default, so a re-selected already-assessed target shows its bar immediately.
- TextureCache.GetOrUploadRenderSurface: resolve the surface's DefaultPaletteId
  so paletted (P8/INDEX16) UI sprites decode instead of falling to magenta.
- ToolbarController.HiddenIds: also hide 0x100001A3 (stack-entry box) — retail
  hides it in HandleSelectionChanged; it was rendering as a stray black box.

Divergence register: AP-47 (meter-visible timing) retired (now faithful); AP-46
rewritten to the BF_ATTACKABLE/BF_PLAYER gate approximation. Full suite green
(2,688 passed / 4 skipped). User-confirmed: name on top, NPC name-only, monster
bar on assess, green flash, no magenta.

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

src/AcDream.App/Rendering/GameWindow.cs

@@ -2026,9 +2026,11 @@ public sealed class GameWindow : IDisposable
                 _selectedObjectController = AcDream.App.UI.Layout.SelectedObjectController.Bind(
                     toolbarLayout,
                     subscribeSelectionChanged: h => SelectionChanged += h,
-                    isHealthTarget:  IsLiveCreatureTarget,
+                    subscribeHealthChanged:    h => Combat.HealthChanged += h,
+                    isHealthTarget:  IsHealthBarTarget,
                     name:            g => Objects.Get(g)?.Name,
                     healthPercent:   g => Combat.GetHealthPercent(g),
+                    hasHealth:       g => Combat.HasHealth(g),
                     stackSize:       g => (uint)(Objects.Get(g)?.StackSize ?? 0),
                     sendQueryHealth: g => _liveSession?.SendQueryHealth(g),
                     datFont:         vitalsDatFont);
@@ -7410,6 +7412,10 @@ public sealed class GameWindow : IDisposable
         // that actually consume the events.
         _inputDispatcher?.Tick();
 
+        // Phase D.5.3a — advance the selected-object overlay flash (0.25s green pulse
+        // on selection, then revert). No-op when nothing is flashing.
+        _selectedObjectController?.Tick(dt);
+
         // Phase K.2 — re-evaluate WantCaptureMouse for the MMB
         // mouse-look state machine. Detect rising/falling edges so the
         // state suspends correctly when ImGui claims the cursor while
@@ -12016,6 +12022,40 @@ public sealed class GameWindow : IDisposable
         return (LiveItemType(guid) & AcDream.Core.Items.ItemType.Creature) != 0;
     }
 
+    // PublicWeenieDesc _bitfield flags (acclient.h:6431-6463) — same bitfield RadarBlipColors reads.
+    private const uint BfPlayer     = 0x8u;    // BF_PLAYER     (acclient.h:6434)
+    private const uint BfAttackable = 0x10u;   // BF_ATTACKABLE (acclient.h:6437)
+
+    /// <summary>
+    /// True if the selected-object strip should show a Health meter for <paramref name="guid"/>.
+    /// Approximates retail's <c>IsPlayer() || pet_owner || ClientCombatSystem::ObjectIsAttackable()</c>
+    /// gate (gmToolbarUI::HandleSelectionChanged :198754) using the server-provided PWD flags:
+    /// the <c>BF_ATTACKABLE</c> bit (monsters) or the <c>BF_PLAYER</c> bit (other players).
+    /// A friendly NPC (e.g. a vendor) has neither bit set → name-only, matching retail.
+    /// The full PK/faction logic of ObjectIsAttackable + the pet case are not ported (divergence AP-46).
+    /// </summary>
+    private bool IsHealthBarTarget(uint guid)
+    {
+        if (guid == _playerServerGuid)
+            return false;
+        if (!_entitiesByServerGuid.ContainsKey(guid))
+            return false;
+
+        uint pwd = _lastSpawnByGuid.TryGetValue(guid, out var spawn)
+                   && spawn.ObjectDescriptionFlags is { } odf ? odf : 0u;
+
+        // Another player → health bar (retail IsPlayer branch).
+        if ((pwd & BfPlayer) != 0)
+            return true;
+
+        // Attackable branch: retail ObjectIsAttackable requires the object to be a CREATURE
+        // first (InqType() & 0x10, acclient_2013_pseudo_c.txt:375406), THEN attackable. A Door
+        // carries the BF_ATTACKABLE bit but is ItemType Misc, so it is never a health-bar target —
+        // require the Creature flag here too (matches retail; excludes attackable doors/objects).
+        bool isCreature = (LiveItemType(guid) & AcDream.Core.Items.ItemType.Creature) != 0;
+        return isCreature && (pwd & BfAttackable) != 0;
+    }
+
 
     /// <summary>
     /// 2026-05-16 — retail-faithful port of

src/AcDream.App/Rendering/TextureCache.cs

@@ -121,9 +121,11 @@ public sealed unsafe class TextureCache : Wb.ITextureCachePerInstance, IDisposab
     /// Surface→SurfaceTexture chain that <see cref="GetOrUpload(uint)"/> uses
     /// for world-geometry materials. This is the correct path for retail UI
     /// chrome + font glyph sheets, which reference RenderSurface directly.
-    /// Palette is null for now (a paletted INDEX16/P8 UI sprite would return
-    /// Magenta — wire a UI palette when one is actually encountered). Returns a
-    /// 1x1 magenta handle on miss.
+    /// Paletted (PFID_P8 / PFID_INDEX16) UI sprites — e.g. the selected-object
+    /// health-bar track 0x0600193E — are decoded against the RenderSurface's own
+    /// <c>DefaultPaletteId</c> (same starting palette <see cref="DecodeFromDats"/>
+    /// uses); non-paletted formats have DefaultPaletteId==0 → palette null. Returns
+    /// a 1x1 magenta handle on miss.
     /// </summary>
     public uint GetOrUploadRenderSurface(uint renderSurfaceId, out int width, out int height, bool nearest = false)
     {
@@ -138,7 +140,14 @@ public sealed unsafe class TextureCache : Wb.ITextureCachePerInstance, IDisposab
         if (_dats.Portal.TryGet<RenderSurface>(renderSurfaceId, out var rs)
             || _dats.HighRes.TryGet<RenderSurface>(renderSurfaceId, out rs))
         {
-            decoded = SurfaceDecoder.DecodeRenderSurface(rs, palette: null);
+            // Resolve the surface's own default palette so paletted UI sprites decode
+            // correctly instead of the magenta fallback (the back-track 0x0600193E behind
+            // the selected-object health bar is PFID_P8/INDEX16). Non-paletted formats
+            // (DefaultPaletteId==0) keep the previous null-palette behaviour unchanged.
+            Palette? palette = rs.DefaultPaletteId != 0
+                ? _dats.Get<Palette>(rs.DefaultPaletteId)
+                : null;
+            decoded = SurfaceDecoder.DecodeRenderSurface(rs, palette);
         }
         else
         {