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

winit/src/platform_specific/wayland/handlers/seat/seat.rs

@@ -18,7 +18,7 @@ impl SeatHandler for SctkState {
     fn new_seat(
         &mut self,
         _conn: &cctk::sctk::reexports::client::Connection,
-        qh: &cctk::sctk::reexports::client::QueueHandle<Self>,
+        _qh: &cctk::sctk::reexports::client::QueueHandle<Self>,
         seat: cctk::sctk::reexports::client::protocol::wl_seat::WlSeat,
     ) {
         self.sctk_events.push(SctkEvent::SeatEvent {