refactor: reorganize project structure and improve user command handling

lib/files.ts

@@ -0,0 +1,13 @@
+export const formatSize = (bytes: number): string => {
+	const units = ["B", "KB", "MB", "GB", "TB"];
+	let size = bytes;
+	let unit = units[0];
+	for (let i = 0; i < units.length; i++) {
+		if (size < 1024 || i === units.length - 1) {
+			unit = units[i];
+			break;
+		}
+		size /= 1024;
+	}
+	return `${size % 1 === 0 ? size : size.toFixed(2)} ${unit}`;
+}