fix multiplayer snapshot disconnect race

Game/scripts/match_sim.gd

@@ -264,6 +264,11 @@ func send_input(bytes: PackedByteArray) -> void:
 
 
 func send_snapshot(peer_id: int, bytes: PackedByteArray) -> void:
+	# A server-side disconnect can leave peer_id in get_peers() until the
+	# current poll batch settles. Do not enter Godot's RPC path for that stale
+	# target; NetSim repeats this check at fire time for delayed sends.
+	if not NetworkManager.can_send_to_peer(peer_id):
+		return
 	_track_sent(bytes.size())
 	NetSim.send(func() -> void: _snapshot.rpc_id(peer_id, bytes), peer_id)
 
@@ -477,6 +482,7 @@ func _disconnect_abusive_peer(peer_id: int, reason: String) -> void:
 	# which does not carry the peer, the reason or a timestamp into the log
 	# stream a container actually captures.
 	ServerLog.warn("peer_kicked", {"peer_id": peer_id, "reason": reason})
+	NetworkManager.invalidate_peer(peer_id)
 	_peer_input_state.erase(peer_id)
 	if multiplayer.multiplayer_peer is ENetMultiplayerPeer:
 		multiplayer.multiplayer_peer.disconnect_peer(peer_id)