fix: revert followRedirectTransport, remove incorrect /github prefix prepend

- followRedirectTransport used http.Client.Do which conflicts with
  ReverseProxy's RequestURI setting → "Request.RequestURI can't be set"
- The auth proxy github case was incorrectly prepending /github to paths
  like /arkylin, causing /github/arkylin to be forwarded to GitHub.
  Just pass the path through directly.

via [HAPI](https://hapi.run)

Co-Authored-By: HAPI <[email protected]>

cmd/main.go

@@ -178,7 +178,7 @@ func buildHandler(cfg *config.Config) (*admin.Handler, http.Handler) {
 			}
 			ghcrProxy.ServeHTTP(w, r)
 		case "github":
-			middleware.StripPrefix("/github", githubProxy).ServeHTTP(w, r)
+			githubProxy.ServeHTTP(w, r)
 		default:
 			dockerProxy.ServeHTTP(w, r)
 		}

internal/proxy/dynamic.go

@@ -13,20 +13,6 @@ import (
 	"mirror-proxy/internal/auth"
 )
 
-// followRedirectTransport 包装 http.RoundTripper，自动跟随 3xx 重定向。
-// 用于 DynamicProxy，避免浏览器在 HTTP 代理上看到 HTTPS→HTTP 的 302 降级警告。
-type followRedirectTransport struct {
-	base http.RoundTripper
-}
-
-func (t *followRedirectTransport) RoundTrip(req *http.Request) (*http.Response, error) {
-	client := &http.Client{
-		Transport:     t.base,
-		CheckRedirect: func(req *http.Request, via []*http.Request) error { return nil },
-	}
-	return client.Do(req)
-}
-
 // DynamicProxy 创建指向任意目标 URL 的反向代理
 func DynamicProxy(targetURL string) http.Handler {
 	target, err := url.Parse(targetURL)
@@ -106,13 +92,11 @@ func DynamicProxy(targetURL string) http.Handler {
 			w.WriteHeader(http.StatusBadGateway)
 			fmt.Fprintf(w, "Proxy error: %s", err.Error())
 		},
-		Transport: &followRedirectTransport{
-			base: &http.Transport{
-				MaxIdleConns:        100,
-				MaxIdleConnsPerHost: 20,
-				IdleConnTimeout:     90 * time.Second,
-				TLSHandshakeTimeout: 10 * time.Second,
-			},
+		Transport: &http.Transport{
+			MaxIdleConns:        100,
+			MaxIdleConnsPerHost: 20,
+			IdleConnTimeout:     90 * time.Second,
+			TLSHandshakeTimeout: 10 * time.Second,
 		},
 	}