fix(event_loop): walk error source chain for BrokenPipe in OtherError

The previous fix checked downcast_ref::<io::Error> directly on the
OtherError payload, but wayland-client wraps the io::Error inside
WaylandError::Io — one level deeper. Downcast failed, is_closed
stayed false, and the panic arm fired anyway.

Replace the single downcast with a source()-chain walk that finds
the io::Error at any depth, matching the same BrokenPipe /
ConnectionReset check already used for the direct IoError arm.

src/event_loop/run.rs

@@ -386,13 +386,25 @@ pub( crate ) fn try_run<A: App>( app: A ) -> Result<(), RunError>
 			Err( calloop::Error::OtherError( ref e ) ) =>
 			{
 				// wayland-client surfaces the closed-socket condition as an
-				// OtherError wrapping an IoError rather than as the
-				// calloop::Error::IoError variant handled above. Treat any
-				// BrokenPipe / ConnectionReset here the same way: exit cleanly.
-				let is_closed = e.downcast_ref::<std::io::Error>()
-					.map( |io| matches!( io.kind(),
-						std::io::ErrorKind::BrokenPipe | std::io::ErrorKind::ConnectionReset ) )
-					.unwrap_or( false );
+				// OtherError wrapping a WaylandError::Io(BrokenPipe) — one
+				// level deeper than a direct io::Error. Walk the source()
+				// chain so we catch it regardless of how many wrapper types
+				// sit between calloop and the raw io::Error.
+				let mut src: Option<&dyn std::error::Error> = Some( e.as_ref() );
+				let mut is_closed = false;
+				while let Some( err ) = src
+				{
+					if let Some( io ) = err.downcast_ref::<std::io::Error>()
+					{
+						if matches!( io.kind(),
+							std::io::ErrorKind::BrokenPipe | std::io::ErrorKind::ConnectionReset )
+						{
+							is_closed = true;
+							break;
+						}
+					}
+					src = err.source();
+				}
 				if is_closed
 				{
 					eprintln!( "ltk: wayland connection lost; exiting" );