Retain surface textures for animations

docs/window-animations-plan.md

@@ -101,6 +101,17 @@ Tests:
 
 Goal: freeze visual contents during movement and enable spawn-out.
 
+Initial retained-record implementation status:
+
+- Tiled animation can retain GPU/dmabuf-backed XDG and Xwayland surface trees.
+- Retained records hold both `GfxTexture` and `SurfaceBuffer` references so the
+  existing buffer release/sync path remains authoritative.
+- Single-pixel buffers can be retained as color records.
+- Async SHM textures are not retained yet because Wry's per-surface SHM
+  front/back textures can be reused by later commits while an animation is still
+  running. Those surfaces fall back to live rendering until an explicit offscreen
+  copy fallback exists.
+
 Implementation shape:
 
 - Add a retained render-record tree for toplevel surfaces.