Fix Godot 4.7 typed array crash: add freed-object filtering in PropertyPool and PerObjectHistory

addons/netfox/servers/data/per-object-history.gd

@@ -11,8 +11,14 @@ func _init(p_history_size: int):
 	_history_size = p_history_size
 
 func subjects() -> Array[Object]:
+	# Filter out freed objects — Godot 4.7 stricter typed arrays
+	# reject invalid references and crash the engine.
+	var valid := []
+	for o in _data.keys():
+		if is_instance_valid(o):
+			valid.append(o)
 	var result := [] as Array[Object]
-	result.assign(_data.keys())
+	result.assign(valid)
 	return result
 
 func is_auth(tick: int, subject: Object) -> bool:

addons/netfox/servers/data/property-pool.gd

@@ -49,8 +49,14 @@ func get_properties_of(subject: Object) -> Array[NodePath]:
 	return properties
 
 func get_subjects() -> Array[Object]:
+	# Filter out freed objects — Godot 4.7 stricter typed arrays
+	# reject invalid references and crash the engine.
+	var valid := []
+	for s in _properties_by_subject.keys():
+		if is_instance_valid(s):
+			valid.append(s)
 	var subjects := [] as Array[Object]
-	subjects.assign(_properties_by_subject.keys())
+	subjects.assign(valid)
 	return subjects
 
 func is_empty() -> bool:

scripts/headless_server.gd

@@ -110,7 +110,14 @@ func _on_first_peer_join(_peer_id: int) -> void:
 		return
 	_first_client_connected = true
 
-	print("[HeadlessServer] First client connected — starting netfox tick loop...")
+	print("[HeadlessServer] First client connected — letting avatar spawn...")
+
+	# Wait TWO frames so PlayerSpawner._handle_new_peer() creates the avatar
+	# BEFORE NetworkTime starts. The tick loop needs at least one subject.
+	await get_tree().process_frame
+	await get_tree().process_frame
+
+	print("[HeadlessServer] Starting netfox tick loop with player subjects...")
 
 	# Start netfox tick loop now that we have at least one player
 	if NetworkTime and NetworkTime.has_method("start"):