Flow 0.4.13 · Dual-stack connections and source diagnostics

网络设置支持 IPv4/IPv6 双栈、独立选择 TCP/uTP、固定监听端口及可选 UPnP。端口绑定失败时回退并显示原因，设置变更提示完全退出重启。新增找源阶段诊断，展示已观察节点、BT 握手、元数据接收及具体失败原因，修复节点失败后仍显示等待元数据的误导提示。保留已有下载和配置，中英文 README 已更新。

Network settings now expose IPv4/IPv6 dual stack, selectable TCP/uTP, a stable listen port and optional UPnP. Binding failures are reported with fallback, and configuration changes clearly require a full restart. Source diagnostics show observed peers, BT handshakes, metadata reception and concrete errors; failed peers no longer appear to be actively supplying metadata. Existing downloads and preferences are retained. Bilingual documentation updated.

Validation: 54 app tests passed; 2 optional player tests skipped. Controlled IPv6 TCP, IPv4 uTP and IPv6 uTP tests resolved magnets, downloaded payloads and verified exact bytes. Packaged engine startup, update signature and SHA-256 checksums verified.

Local listener checks do not prove internet reachability. UPnP router mapping success is unverified. These changes cannot guarantee availability of rare torrents; no proprietary source network or BEP 55 hole punching is implemented.

Downloads: Flow-Setup-0.4.13-x64.exe is the installer; Flow-0.4.13-windows-x64-portable.zip is the portable package; Flow.exe replaces an existing copy. Fully exit Flow before upgrading.