build: drop the unused raw-window-handle declaration

More of the retired wgpu-path residue, after the wgpu/bytemuck sweep.
Nothing in this crate names raw-window-handle anywhere — src, tests, or build
script.

Verified by building, not just grepping: a declaration can exist to pin
or unify a transitive version. It did not here — the workspace lock
resolves byte-identically before and after (531 packages, no version
moved), so this changes nothing that compiles.

raw-window-handle remains a real dependency of cce-ui (wayland.rs), and
pollster of cce-status-interface; both keep their declarations.
pollster STAYS here and is now marked as such: stats.rs:148 blocks on the
async volume read with pollster::block_on. A first pass removed it — the
build caught it immediately, which is why these get compiled rather than
grepped.

 Cargo.toml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Cargo.toml b/Cargo.toml
index 0dddcf5..afd6e89 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,7 +10,7 @@ calloop = "0.13.0"
 calloop-wayland-source = "0.3.0"
 wayland-client = { version = "0.31", features = ["system"] }
 xkeysym = "0.2"
-raw-window-handle = "0.6"
+# Real dependency: stats.rs blocks on the async volume read.
 pollster = "0.4"
 glyphon = "0.8"
 tokio = { version = "1", features = ["full"] }