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>

src/AcDream.App/UI/UiElement.cs

@@ -9,6 +9,12 @@ namespace AcDream.App.UI;
 [System.Flags]
 public enum AnchorEdges { None = 0, Left = 1, Top = 2, Right = 4, Bottom = 8 }
 
+/// <summary>Retail dat cursor media attached to a UI state.</summary>
+public readonly record struct UiCursorMedia(uint File, int HotspotX, int HotspotY)
+{
+    public bool IsValid => File != 0;
+}
+
 /// <summary>
 /// Base class for every UI widget in the retained-mode tree.
 ///
@@ -40,9 +46,56 @@ public abstract class UiElement
     /// </summary>
     public uint EventId { get; internal set; }
 
+    /// <summary>
+    /// Dat LayoutDesc element id for widgets imported from retail UI data.
+    /// Zero for runtime-created helper widgets. This is intentionally separate
+    /// from <see cref="EventId"/>: event ids are runtime-local, while this id is
+    /// stable across retail layout dumps, decomp references, and UI probes.
+    /// </summary>
+    public uint DatElementId { get; internal set; }
+
     /// <summary>Human-readable name for debugging / FindByName.</summary>
     public string? Name { get; init; }
 
+    private readonly Dictionary<string, UiCursorMedia> _stateCursors = new();
+
+    /// <summary>Retail MediaDescCursor entries keyed by UIStateId.ToString(), or "" for DirectState.</summary>
+    public IReadOnlyDictionary<string, UiCursorMedia> StateCursors => _stateCursors;
+
+    /// <summary>Active state name used for cursor media. Stateful dat widgets override this.</summary>
+    public virtual string ActiveCursorStateName => "";
+
+    public void SetStateCursors(IReadOnlyDictionary<string, UiCursorMedia> cursors)
+    {
+        _stateCursors.Clear();
+        foreach (var kv in cursors)
+        {
+            if (kv.Value.IsValid)
+                _stateCursors[kv.Key] = kv.Value;
+        }
+    }
+
+    public UiCursorMedia ActiveCursor()
+        => CursorForState(ActiveCursorStateName, allowFallback: true);
+
+    public UiCursorMedia CursorForState(string stateName, bool allowFallback = true)
+    {
+        if (!string.IsNullOrEmpty(stateName)
+            && _stateCursors.TryGetValue(stateName, out var named)
+            && named.IsValid)
+            return named;
+
+        if (!allowFallback)
+            return default;
+
+        if (_stateCursors.TryGetValue("", out var direct) && direct.IsValid)
+            return direct;
+        if (_stateCursors.TryGetValue("Normal", out var normal) && normal.IsValid)
+            return normal;
+
+        return default;
+    }
+
     // ── Geometry ────────────────────────────────────────────────────────
     /// <summary>X in the parent's local pixel space.</summary>
     public float Left   { get; set; }
@@ -130,6 +183,14 @@ public abstract class UiElement
     /// self-driven interior drag such as text selection). Default false.</summary>
     public virtual bool HandlesClick => false;
 
+    /// <summary>
+    /// Optional game-object target used by item-use cursor/target mode when this UI
+    /// element represents a target that is not its visible item icon. Example:
+    /// the status-bar backpack button and paperdoll both mean "self" for a
+    /// health-kit-style use-with-target action.
+    /// </summary>
+    public Func<uint>? UseTargetGuidProvider { get; set; }
+
     /// <summary>Minimum size enforced while resizing.</summary>
     public float MinWidth { get; set; } = 40f;
     public float MinHeight { get; set; } = 40f;