vjudge: handle problem resync & fix uoj

packages/hydrooj/src/service/storage.ts

@@ -325,7 +325,7 @@ class LocalStorageService {
 
     async get(target: string, path?: string) {
         target = resolve(this.dir, convertPath(target));
-        if (!existsSync(target)) throw new Error('File not found');
+        if (!existsSync(target)) throw new Error(`File not found: ${target}`);
         if (path) await copyFile(target, path);
         return createReadStream(target);
     }