Flow 0.4.12 · Tracker refresh feedback and configuration visibility

保存 Tracker 订阅后显示明确反馈，并在后台加载候选，避免打断下载任务。Tracker 页面显示加载状态、去重候选数量及来源刷新/缓存详情，区分已载入引擎的地址与待应用候选。保存配置不再等待网络刷新，修复相关超时。候选查询与应用到任务分别提示；已载入不等于已连接，当前未提供逐 Tracker 的节点归因。中英文 README 已更新。

Tracker subscription saves now provide clear feedback and load candidates in the background without reloading downloads. The Tracker page shows loading state, deduplicated candidate counts and source refresh/cache details, distinguishing loaded engine configuration from unapplied candidates. Saving settings no longer waits for network refreshes. Queries and candidate application have separate confirmations. Loaded does not mean connected; per-Tracker peer attribution is not available. Bilingual README updated.

Validation: 47 app tests passed, 2 optional player tests ignored. Packaged backend startup, signed update manifest and SHA-256 checksums verified.

Downloads: Flow-Setup-0.4.12-x64.exe is the installer; Flow-0.4.12-windows-x64-portable.zip is the portable package. Fully exit Flow before upgrading.