action select: add onchange callback

src/lib/ActionSelect.svelte

@@ -24,6 +24,7 @@
 		tabbable?: boolean;
 		options: ActionSelectOption[];
 		class?: ClassValue | null | undefined;
+		onchange?: (value: ActionSelectOption | undefined) => void;
 	}
 
 	let {
@@ -33,14 +34,18 @@
 		stateless = false,
 		tabbable = true,
 		options,
-		class: classValue
+		class: classValue,
+		onchange
 	}: Props = $props();
 
 	const select = new Select<ActionSelectOption>({
 		value: () => value,
 		onValueChange: (val) => {
 			val?.onchoose?.(val);
-			if (!stateless) value = val;
+			if (!stateless) {
+				value = val;
+				onchange?.(val);
+			}
 		}
 	});
 </script>