fix(wayland): graceful exit on compositor disconnect

Replace 3 panicking unwrap() in cosmic-app-list/wayland_handler.rs
(event loop dispatch + 2 conn.flush in screencopy) with logged
errors that break/return None instead.

Wrap cosmic-applets/main.rs entry point in panic::catch_unwind to
catch panics propagating from libcosmic/iced/winit (which we cannot
patch locally without forking) when the COSMIC compositor closes
the Wayland connection at logout. This eliminates the cascade of
~12 SIGABRT coredumps observed at session shutdown.

Panic strategy is unwind (default), catch_unwind is sound here.

Leyoda 2026 – GPLv3

cosmic-app-list/src/wayland_handler.rs

@@ -388,7 +388,10 @@ impl CaptureData {
                 },
             )
             .unwrap();
-        self.conn.flush().unwrap();
+        if let Err(err) = self.conn.flush() {
+            tracing::error!("Wayland flush failed during screencopy session create: {err}");
+            return None;
+        }
 
         let formats = session
             .wait_while(|data| data.formats.is_none())
@@ -437,7 +440,10 @@ impl CaptureData {
                 session: capture_session.clone(),
             },
         );
-        self.conn.flush().unwrap();
+        if let Err(err) = self.conn.flush() {
+            tracing::error!("Wayland flush failed during screencopy capture: {err}");
+            return None;
+        }
 
         // TODO: wait for server to release buffer?
         let res = session
@@ -709,7 +715,10 @@ pub(crate) fn wayland_handler(
         if app_data.exit {
             break;
         }
-        event_loop.dispatch(None, &mut app_data).unwrap();
+        if let Err(err) = event_loop.dispatch(None, &mut app_data) {
+            tracing::error!("Wayland event loop terminated: {err}");
+            break;
+        }
     }
 }