Move library album and track operations into shared server modules

web-player/src/lib/server/forms/fields.ts

@@ -6,3 +6,10 @@ export function formFile(form: FormData, key: string): File | null {
 	const value = form.get(key);
 	return value instanceof File && value.size > 0 ? value : null;
 }
+
+export function formIds(form: FormData, key: string): string[] {
+	return form
+		.getAll(key)
+		.flatMap((value) => String(value).split(','))
+		.filter(Boolean);
+}