fix(appd): remove abort_sender entry when session supervisor exits

When a runtime process exits naturally (not via TerminateApp) the
oneshot Sender remained in abort_senders until shutdown_all().
Add remove_abort_sender() and call it at the normal exit path in
supervise() to release the entry immediately.

crates/weft-appd/src/main.rs

@@ -101,6 +101,10 @@ impl SessionRegistry {
         }
     }
 
+    pub(crate) fn remove_abort_sender(&mut self, session_id: u64) {
+        self.abort_senders.remove(&session_id);
+    }
+
     pub(crate) fn subscribe(&self) -> tokio::sync::broadcast::Receiver<Response> {
         self.broadcast.subscribe()
     }

crates/weft-appd/src/runtime.rs

@@ -286,6 +286,7 @@ pub(crate) async fn supervise(
     {
         let mut reg = registry.lock().await;
         reg.set_state(session_id, AppStateKind::Stopped);
+        reg.remove_abort_sender(session_id);
         let _ = reg.broadcast().send(Response::AppState {
             session_id,
             state: AppStateKind::Stopped,