WIP checkpoint: Implement avatar loader and customization UI in Godot

scripts/avatar/avatar_catalog.gd

@@ -41,12 +41,14 @@ func load_catalog(path: String = _catalog_path) -> Error:
 	var json_text: String = file.get_as_text()
 	file.close()
 
-	var json: JSONParseResult = JSON.parse_string(json_text)
-	if json == null:
+	var result: Variant = JSON.parse_string(json_text)
+	if result == null or not result is Dictionary:
 		catalog_load_failed.emit("Invalid JSON in catalog: %s" % path)
 		return ERR_PARSE_ERROR
 
-	if not json is Dictionary or not json.has("assets"):
+	var json: Dictionary = result as Dictionary
+
+	if not json.has("assets"):
 		catalog_load_failed.emit("Catalog missing 'assets' key")
 		return ERR_INVALID_DATA
 
@@ -56,6 +58,11 @@ func load_catalog(path: String = _catalog_path) -> Error:
 	return OK
 
 
+## Check if the catalog has been loaded.
+func is_loaded() -> bool:
+	return _loaded
+
+
 ## Resolve an asset by its ID.
 ## Returns a Dictionary with keys: type, slot, path, version, etc.
 ## Returns null if the asset ID is not found.