fix: Document title with slashes produces folders in exported zip file

closes #2036

server/utils/fs.js

@@ -2,6 +2,14 @@
 import path from "path";
 import fs from "fs-extra";
 
+export function serializeFilename(text: string): string {
+  return text.replace(/\//g, "%2F").replace(/\\/g, "%5C");
+}
+
+export function deserializeFilename(text: string): string {
+  return text.replace(/%2F/g, "/").replace(/%5C/g, "\\");
+}
+
 export function requireDirectory<T>(dirName: string): [T, string][] {
   return fs
     .readdirSync(dirName)