yoda: cargo fix --lib across all crates — drop ~115 trivial warnings

Auto-applied suggestions (unused imports, _-prefixed unused params,
redundant mutability) on iced_core, iced_widget, iced_runtime, iced_winit,
iced_wgpu, iced_graphics, iced_tiny_skia. From 170 warnings down to 55.

Leyoda 2026 – GPLv3

widget/src/svg.rs

@@ -31,7 +31,6 @@ use crate::core::{
 
 #[cfg(feature = "a11y")]
 use std::borrow::Cow;
-use std::marker::PhantomData;
 use std::path::PathBuf;
 
 pub use crate::core::svg::Handle;