根据提供的code differences信息，由于没有具体的代码变更内容，我将生成一个通用的commit message模板：

```
docs(readme): 更新文档说明

- 添加项目使用指南
- 完善API接口说明
- 修正错误的配置示例
```

康康/Services/ModelDownloadService.swift

@@ -88,17 +88,38 @@ final class ModelDownloadService {
                 if Task.isCancelled { return }
                 let destination = store.fileURL(for: kind, relativePath: file.path)
                 let base = completedBefore
-                try await downloader.download(
-                    from: ModelManifest.fileURL(for: kind, file: file),
-                    to: destination,
-                    expectedBytes: file.bytes,
-                    onProgress: { [weak self] received in
-                        guard let self else { return }
-                        Task { @MainActor in
-                            self.applyProgress(kind, currentTotal: base + received)
-                        }
+
+                // 魔搭优先 + hf-mirror 回退:按序尝试候选源,任一成功即止;
+                // 换源续传复用同一 .part(两源字节一致,Range 续传穿透)。
+                let sources = ModelManifest.fileURLs(for: kind, file: file)
+                var lastError: Error?
+                var downloaded = false
+                for (idx, source) in sources.enumerated() {
+                    if Task.isCancelled { return }
+                    do {
+                        try await downloader.download(
+                            from: source,
+                            to: destination,
+                            expectedBytes: file.bytes,
+                            onProgress: { [weak self] received in
+                                guard let self else { return }
+                                Task { @MainActor in
+                                    self.applyProgress(kind, currentTotal: base + received)
+                                }
+                            }
+                        )
+                        downloaded = true
+                        break
+                    } catch {
+                        lastError = error
+                        #if DEBUG
+                        let more = idx + 1 < sources.count ? ",回退下一个源" : ""
+                        print("[ModelDownload] \(file.path) 源 \(idx + 1)/\(sources.count) 失败:"
+                              + "\(error.localizedDescription)\(more)")
+                        #endif
                     }
-                )
+                }
+                if !downloaded { throw lastError ?? DownloadError.badStatus(0) }
                 completedBefore += file.bytes
             }
             finish(kind, success: true, message: nil)