修复无法获得pdf的问题

src/modules/lecture/infrastructure/platform/paths.ts

@@ -19,28 +19,38 @@ export function normalizeExecutablePath(input: string): string {
 
 /** Join path segments using Zotero PathUtils (cross-platform). */
 export function joinPath(...parts: string[]): string {
-  return PathUtils.join(...parts.filter(Boolean));
+  const filtered = parts.filter(Boolean);
+  if (!filtered.length) return "";
+  try {
+    return PathUtils.join(...filtered);
+  } catch (e) {
+    ztoolkit.log("[ChatPapers] PathUtils.join failed", filtered, e);
+    throw e;
+  }
 }
 
-/** Normalize a filesystem path for the current OS. */
+/** Normalize user-provided storage directory paths (prefs). */
 export function normalizeStoragePath(input: string): string {
   const trimmed = (input || "").trim();
   if (!trimmed) return "";
-  const joined = trimmed.replace(/[\\/]+/g, "/");
-  if (/^[A-Za-z]:\//.test(joined)) {
-    const drive = joined.slice(0, 2);
-    const rest = joined
-      .slice(2)
+
+  const unified = trimmed.replace(/\\/g, "/").replace(/\/+/g, "/");
+
+  const winMatch = unified.match(/^([A-Za-z]:)(\/.*)?$/);
+  if (winMatch) {
+    const drive = winMatch[1];
+    const rest = (winMatch[2] || "")
       .split("/")
       .filter((part) => part && part !== ".")
       .join("\\");
-    return `${drive}\\${rest}`.replace(/\\+$/, "");
+    return rest ? `${drive}\\${rest}` : drive;
   }
-  return joined
-    .split("/")
-    .filter((part) => part && part !== ".")
-    .join("/")
-    .replace(/\/+$/, "");
+
+  const absolute = unified.startsWith("/");
+  const parts = unified.split("/").filter((part) => part && part !== ".");
+  let result = parts.join("/");
+  if (absolute) result = `/${result}`;
+  return result.replace(/\/+$/, "") || (absolute ? "/" : "");
 }
 
 /** Safe single path segment for file or directory names (cross-platform). */