修复无法获得pdf的问题

src/modules/storage/sessions.ts

@@ -1,8 +1,8 @@
 import type { ChatMessage } from "../llm/types";
 
 function sessionDir(): string {
-  const profile = (Zotero as any).Profile?.dir || (Zotero as any).getProfileDirectory?.()?.path;
-  if (!profile) {
+  const profile = (Zotero as any).Profile?.dir;
+  if (!profile || typeof profile !== "string") {
     throw new Error("Cannot resolve Zotero profile directory");
   }
   return PathUtils.join(profile, "chatpapers", "sessions");