Update Mihomo configuration and documentation for clarity

- Revised comments in `config.example.yaml` to enhance understanding of Mihomo integration, including environment variable usage and Docker Compose setup.
- Updated `docker-compose.yml` comments to clarify the relationship between the gateway and Mihomo service.
- Enhanced `GATEWAY_RUN.md` to provide clearer instructions on configuring Mihomo parameters and their usage in the gateway.

internal/proxy/mihomo.go

@@ -9,6 +9,8 @@ import (
 )
 
 // NewMihomoForward proxies /api/{alias}/mihomo/... to Mihomo external-controller (REST + WebSocket).
+// Используется Rewrite (Go 1.20+): очищается RequestURI и задаётся абсолютный URL — иначе строгий upstream
+// и WebSocket upgrade могут отвечать 400 (см. аналогично Telemt в forward.go).
 func NewMihomoForward(
 	target *url.URL,
 	stripPrefix string,
@@ -23,27 +25,30 @@ func NewMihomoForward(
 		rt = http.DefaultTransport
 	}
 	rp := &httputil.ReverseProxy{
-		Director: func(req *http.Request) {
-			NormalizeRequestURLPath(req)
-			p := req.URL.Path
+		Rewrite: func(pr *httputil.ProxyRequest) {
+			NormalizeRequestURLPath(pr.In)
+			p := pr.In.URL.Path
 			if !strings.HasPrefix(p, stripPrefix) {
 				return
 			}
-			rest := strings.TrimPrefix(p, stripPrefix)
-			rest = strings.TrimPrefix(rest, "/")
-			q := req.URL.RawQuery
+			rest := strings.TrimPrefix(strings.TrimPrefix(p, stripPrefix), "/")
 			dest := JoinPathPrefix(target, "/", rest)
-			req.URL.Scheme = dest.Scheme
-			req.URL.Host = dest.Host
-			req.URL.Path = dest.Path
-			req.URL.RawQuery = q
-			req.Host = dest.Host
-			req.Header.Del("Authorization")
+			du := *dest
+			du.RawQuery = pr.In.URL.RawQuery
+			out := pr.Out
+			out.URL = &du
+			out.Host = du.Host
+			out.RequestURI = ""
+			out.Proto = "HTTP/1.1"
+			out.ProtoMajor = 1
+			out.ProtoMinor = 1
+			out.Header.Del("Authorization")
 			if auth != "" {
-				req.Header.Set("Authorization", auth)
+				out.Header.Set("Authorization", auth)
 			}
 		},
-		Transport: rt,
+		Transport:      rt,
+		FlushInterval:  -1,
 		ErrorHandler: func(w http.ResponseWriter, r *http.Request, err error) {
 			errHandler(w, r, err)
 		},
@@ -70,4 +75,3 @@ func MihomoJSONError(w http.ResponseWriter, code, msg string) {
 		"error": map[string]string{"code": code, "message": msg},
 	})
 }
-