docs: Scene::at_including_grid is gone — the hit-test is Scene::at

Both CLAUDE.md and the header comment on src/items.rs sent the reader to
`Scene::at_including_grid` for how a drag over the desktop background reaches
this client. cce-compositor removed that entry point on 2026-08-26 in b82a0ee
("let the grid layer be hit-tested through its input region"): the grid is
hit-tested by the ordinary `Scene::at` now, through the input region this
client publishes, so the separate call is not merely renamed but unnecessary.

A dead cross-crate reference is the expensive kind — it reads as a lead and
costs a search of the wrong crate before it turns up nothing.

Comment-only in items.rs; cce-grid builds unchanged.

Co-Authored-By: Claude Opus 5 <[email protected]>

 CLAUDE.md    | 4 +++-
 src/items.rs | 3 ++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/CLAUDE.md b/CLAUDE.md
index ab47c53..d328ff6 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -44,7 +44,9 @@ everywhere else.
 ## Desktop items (`src/items.rs`)
 
 Images pinned to the world canvas. The compositor routes a drag over the
-desktop background onto this client (its `Scene::at_including_grid`), so a
+desktop background onto this client (its `Scene::at`, which has hit-tested the
+grid layer through its input region since cce-compositor@b82a0ee — the separate
+`at_including_grid` entry point it used to need is gone), so a
 drop arrives at `handle_drop`; `drop_mimes()` declares the accepted flavors in
 preference order. Pixels win whenever they are offered (`image/png`,
 `image/jpeg`, `image/gif`, `image/webp`) — no fetch, no ambiguity. Below them
diff --git a/src/items.rs b/src/items.rs
index 0a5f424..ecf5d0b 100644
--- a/src/items.rs
+++ b/src/items.rs
@@ -1,7 +1,8 @@
 // Desktop items: images pinned to the world canvas.
 //
 // A drop on the desktop background lands here (the compositor routes drags
-// over the background onto the grid client — see its `Scene::at_including_grid`).
+// over the background onto the grid client — see its `Scene::at`, which hit-tests
+// the grid layer through its input region since cce-compositor@b82a0ee).
 // Each item is saved to the desktop folder AND recorded in a sidecar with the
 // virtual-canvas position it was dropped at, so it reappears in the same world
 // spot next session. Nothing here touches the GPU: the caller uploads the