fix(ui): D.2b-B — address phase-boundary review (burden % saturation + equipped filter)

Opus phase-boundary review findings:
- I1 (faithfulness): LoadToPercent now computes from the CLAMPED fill
  (floor(LoadToFill(load)*300)), so the burden % SATURATES at 300% like retail
  (decomp 176544-176576 clamps arg2 to [0,1] BEFORE the *300). The old
  floor(load*100) over-read to 400% at 4x capacity. Golden test corrected.
- I2 (partition): exclude equipped items (CurrentlyEquippedLocation != None) from
  the contents grid + selector — a mid-session self-wield routes them through
  MoveItem(item, WielderGuid=player) into GetContents(player); retail's gm3DItemsUI
  shows pack contents only. New conformance test.
- N1: drop dead 'using System.Collections.Generic' (left after the 383e8b7 cleanup).
- N3: AP-48 risk wording (drift can be low OR high vs server EncumbranceVal).

Build green; BurdenMath 17, InventoryController/UiMeter 10 tests pass.

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

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

@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Generic;
 using System.Numerics;
 using AcDream.Core.Items;
 
@@ -137,6 +136,11 @@ public sealed class InventoryController
         {
             var item = _objects.Get(guid);
             if (item is null) continue;
+            // Equipped items belong on the paperdoll (Sub-phase C), never in the pack grid or
+            // the side-bag list. A mid-session self-wield routes an item through
+            // MoveItem(item, WielderGuid=player), so it transiently lands in GetContents(player);
+            // retail's gm3DItemsUI shows pack contents only, gated on the wielded location.
+            if (item.CurrentlyEquippedLocation != EquipMask.None) continue;
             bool isBag = item.Type.HasFlag(ItemType.Container) || item.ItemsCapacity > 0;
             var list = isBag ? _containerList : _contentsGrid;
             if (list is null) continue;