fix: add #[must_use] to AbortHandle and clear message queues on disconnect

src/client.rs

@@ -1106,6 +1106,10 @@ impl Client {
         // checks the socket, but this ordering avoids a confusing state window.
         self.is_connected.store(false, Ordering::Release);
         self.retried_group_messages.invalidate_all();
+        // Drop per-chat message queue senders so workers exit via channel close.
+        // Without this, stale workers from the old connection survive reconnects
+        // holding outdated signal/crypto state.
+        self.message_queues.invalidate_all();
         // Clear pending retries so stale keys from detached scopeguard
         // cleanup don't suppress the first retry after reconnect.
         self.pending_retries

wacore/src/runtime.rs

@@ -64,6 +64,7 @@ pub trait Runtime: Send + Sync + 'static {
 /// Uses `std::sync::Mutex` internally so that the handle is `Send + Sync`,
 /// which is required because it may be stored inside structs shared across
 /// tasks (e.g. `NoiseSocket` behind an `Arc`).
+#[must_use = "dropping an AbortHandle aborts the task; use .detach() for fire-and-forget"]
 pub struct AbortHandle {
     abort_fn: std::sync::Mutex<Option<Box<dyn FnOnce() + Send + 'static>>>,
 }