fix(ui): retail target-cursor shape (pending over UI, world-object driven) + visible UseDone refusals

Visual gate round 2 (user, retail oracle): the target cursor over UI must
be the 0x27 four-arrows PENDING cursor — retail's UpdateCursorState
(0x00564630) keys valid/invalid solely off the SmartBox found object,
i.e. the WORLD entity under the cursor. And "can't heal myself" turned
out to be TWO stacked causes, both fixed:

- Cursor: UI hover no longer forces TargetInvalid (that arm was a
  non-retail invention) and the doll/status-bar hover providers are
  gone (UiElement.UseTargetGuidProvider deleted). Valid/invalid now
  come from (a) a hovered occupied item slot's own item, or (b) the
  world entity under the cursor via a new worldTargetProvider — the
  B.4b screen-rect picker extracted into GameWindow.PickWorldGuidAtCursor
  and shared by click + hover.
- Self-heal: the world picker always skipped the local player
  (skipServerGuid), so clicking your own toon in target mode could
  never acquire self. Target-use picks now include self (retail lets
  you kit-heal yourself by clicking your character); plain selection
  keeps the exclusion. The doll click still self-targets.
- Silent refusals: the [use-target] log proved the UseWithTarget action
  WAS sent (kit 0x00220008 / TargetType 0x10, target self) — ACE
  refused with WeenieError.YouArentTrainedInHealing (0x04FC) and we
  never parsed UseDone (0x01C7). Now dispatched + surfaced as a chat
  line via WeenieErrorText (interim subset map, register AP-74, #166
  ports the retail String-table lookup).

Full suite green (3,295).

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

src/AcDream.Core.Net/GameEventWiring.cs

@@ -306,6 +306,20 @@ public static class GameEventWiring
             Console.WriteLine($"[B-Drag] InventoryServerSaveFailed guid=0x{p.Value.ItemGuid:X8} err=0x{p.Value.WeenieError:X} rolledBack={rolledBack} item={itemInfo}");
         });
 
+        // UseDone (0x01C7) — the Use/UseWithTarget completion signal. A non-zero
+        // code is a WeenieError refusal ("You are not trained in healing!" etc.);
+        // retail surfaces the string-table text as a chat line. Interim text map:
+        // WeenieErrorText (#166 / register AP-74). Without this line a refused
+        // kit-heal looks like "nothing happened" — the 2026-07-03 session bug.
+        dispatcher.Register(GameEventType.UseDone, e =>
+        {
+            uint? err = GameEvents.ParseUseDone(e.Payload.Span);
+            if (err is null) return;
+            Console.WriteLine($"[use-done] err=0x{err.Value:X4}");
+            if (err.Value != 0)
+                chat.OnSystemMessage(WeenieErrorText.For(err.Value), chatType: 0);
+        });
+
         // B-Wire: CloseGroundContainer (0x0052) — server closed a ground-container
         // view. No table change (the view is UI-only, wired in container-open); log.
         dispatcher.Register(GameEventType.CloseGroundContainer, e =>