Hysteria server: Fix Unix masquerade socket path

[XXcipherX]

Problem

The current Xray code handles Unix-socket targets in the following order:

case "", "unix":
    u = &url.URL{Scheme: "http", Host: "localhost"}
    path := u.Path

    dialer := &net.Dialer{Timeout: 30 * time.Second}
    transport = transport.Clone()
    transport.Proxy = nil
    transport.DialContext = func(ctx context.Context, network, addr string) (net.Conn, error) {
        return dialer.DialContext(ctx, "unix", path)
    }

The original parsed URL is overwritten before its path is saved:

u = &url.URL{Scheme: "http", Host: "localhost"}

The replacement URL has an empty Path, so the next assignment always produces:

path == ""

Consequently, the custom transport effectively attempts:

dialer.DialContext(ctx, "unix", "")

On Linux, this fails with an error similar to:

dial unix: missing address

The Hysteria masquerade handler then returns 502 Bad Gateway, while Xray logs:

HTTP reverse proxy error

This affects all supported Unix-socket target formats, not just one particular URL form, because the parsed socket path is discarded in every case.

Upstream behavior

In the upstream Hysteria implementation, the socket path is saved before constructing the synthetic HTTP target:

socketPath := parsedURL.Path

Only after that does it return the target used by httputil.ReverseProxy:

return &url.URL{
    Scheme: "http",
    Host:   "localhost",
}, transport, nil

The custom transport therefore captures the original socket path:

transport.DialContext = func(ctx context.Context, _, _ string) (net.Conn, error) {
    return dialer.DialContext(ctx, "unix", socketPath)
}

The incorrect ordering was introduced while adapting this logic in #6565 it is not caused by the upstream Hysteria implementation.

Fix

Save u.Path before replacing u with the synthetic http://localhost target:

case "", "unix":
    path := u.Path
    u = &url.URL{Scheme: "http", Host: "localhost"}

This preserves the original Unix socket address while leaving HTTP and HTTPS masquerade behavior unchanged.

[LjhAUMEM]

这里确实同步错了，感谢修复

改的代码行数少的话也不用写这么多描述，看代码就可以知道意图