tss-http：扩展buffer长度

http-server/main.cpp

@@ -217,7 +217,7 @@ int main(int argc, char** argv)
         // 定义分块回调（严格匹配 ContentProvider 签名）
         auto provider = [file](size_t offset, size_t length, httplib::DataSink& sink) {
             file->seekg(offset);
-            const size_t chunk_size = std::min<size_t>(65536, length);   // 64KB或剩余长度
+            const size_t chunk_size = std::min<size_t>(1024 * 1024, length);   // 64KB或剩余长度
             std::vector<char> buffer(chunk_size);
 
             size_t remaining = length;