switch to element defined span lens + better size fn

Cargo.toml

@@ -11,7 +11,7 @@ winit = "0.30.12"
 wgpu = "27.0.1"
 bytemuck = "1.23.1"
 image = "0.25.6"
-cosmic-text = "0.14.2"
+cosmic-text = "0.15.0"
 unicode-segmentation = "1.12.0"
 fxhash = "0.2.1"
 arboard = { version = "3.6.1", features = ["wayland-data-control"] }