feat(ui): D.2b item interaction + retail cursors + live character sheet

Lands the codex-worktree D.2b stream plus the extraction the 2026-07-02
UI architecture review mandated before commit:

- ItemInteractionController: single owner of double-click use/equip/
  container-open, targeted-use mode (health kits), drag-out drop;
  toolbar shortcut drags don't drop the real item. ItemEquipRules for
  multi-slot (coat) coverage via equip masks.
- Cursor phase: CursorFeedbackController (semantic priority chain:
  drag > resize > window-move > target-mode > text) + RetailCursorCatalog
  (enums 0x27/0x28/0x29, hotspot 14,14; ClientUISystem::UpdateCursorState
  0x00564630) resolved through the portal EnumIDMap chain by
  RetailCursorResolver; RetailCursorManager applies dat cursor art to the
  OS cursor. Register row AP-72 covers the OS standard-cursor fallback.
- Character window goes live: CharacterSheetProvider owns sheet assembly,
  XP-curve/raise-cost math and the raise flow — extracted out of
  GameWindow per Code Structure Rule 1 instead of committing the ~430-line
  feature body there. Optimistic XP/credit debits go through eventful
  store APIs (new ClientObjectTable.UpdateInt64Property +
  LocalPlayerState.DebitIntProperty/DebitInt64Property) instead of raw
  property-dictionary writes; register row AP-73 covers the still-missing
  raise ledger (#163).
- RetailWindowFrame: the shared nine-slice window mount recipe; the
  character window uses it, remaining windows migrate via #164.
- Status-bar buttons toggle inventory/character windows; retail row-major
  backpack ordering; WorldSession.SendUseWithTarget + raise/train sends.

GameWindow shrinks 14,214 -> 13,877 lines despite the new features; the
sheet/raise logic is unit-tested in CharacterSheetProviderTests instead
of trapped in the god object. Build green; full suite 3,286 tests pass.

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

tests/AcDream.App.Tests/UI/UiItemListGridTests.cs

@@ -12,6 +12,14 @@ public class UiItemListGridTests
         Assert.Equal((36f, 36f), UiItemList.CellOffset(4, 3, 36, 36)); // col 1, row 1
     }
 
+    [Fact]
+    public void CellOffset_ColumnMajor_UsesLogicalRows()
+    {
+        Assert.Equal((0f, 0f),   UiItemList.CellOffset(0, 3, 7, UiItemListFlow.ColumnMajor, 36, 36));
+        Assert.Equal((0f, 36f),  UiItemList.CellOffset(1, 3, 7, UiItemListFlow.ColumnMajor, 36, 36));
+        Assert.Equal((36f, 0f),  UiItemList.CellOffset(3, 3, 7, UiItemListFlow.ColumnMajor, 36, 36));
+    }
+
     [Fact]
     public void GridMode_PositionsCellsInColumns()
     {
@@ -26,6 +34,25 @@ public class UiItemListGridTests
         Assert.Equal(36f, c4.Height);
     }
 
+    [Fact]
+    public void GridMode_ColumnMajor_PositionsCellsDownRowsFirst()
+    {
+        var list = new UiItemList
+        {
+            Columns = 3,
+            Flow = UiItemListFlow.ColumnMajor,
+            CellWidth = 36,
+            CellHeight = 36,
+        };
+        list.Flush();
+        for (int i = 0; i < 7; i++) list.AddItem(new UiItemSlot());
+
+        var c3 = list.GetItem(3)!;
+        Assert.Equal(36f, c3.Left);
+        Assert.Equal(0f, c3.Top);
+    }
+
+
     [Fact]
     public void FillMode_SizesSingleCellToList()
     {