feat(vfx): bind effects to live animated poses

src/AcDream.Core/Vfx/IEntityEffectPoseSource.cs

@@ -0,0 +1,24 @@
+using System.Numerics;
+
+namespace AcDream.Core.Vfx;
+
+/// <summary>
+/// Read-only view of the final pose used by entity-attached effects.
+/// Implementations publish poses on the update/render thread after root motion,
+/// animation, and equipped-child composition have completed.
+/// </summary>
+public interface IEntityEffectPoseSource
+{
+    bool TryGetRootPose(uint localEntityId, out Matrix4x4 rootWorld);
+
+    bool TryGetPartPose(uint localEntityId, int partIndex, out Matrix4x4 partLocal);
+}
+
+/// <summary>
+/// Optional spatial companion for consumers, such as object lights, whose
+/// render registration is scoped to the owner's current AC cell.
+/// </summary>
+public interface IEntityEffectCellSource
+{
+    bool TryGetCellId(uint localEntityId, out uint cellId);
+}