fix(link): actually bound the server connect with a timeout [CI]

backend/fleet/src/Fleet.Link/FleetLink.cs

@@ -64,6 +64,9 @@ public sealed class FleetLinkOptions
     /// <summary>Optional reason for an orderly client shutdown, so the server can distinguish updates from service stops.</summary>
     public Func<string>? ShutdownReason { get; init; }
 
+    /// <summary>连上服务器的整个过程（TCP、TLS、升级）最多等多久；卡住就放弃，由外层退避重试。</summary>
+    public TimeSpan ConnectTimeout { get; init; } = TimeSpan.FromSeconds(20);
+
     public TimeSpan HeartbeatInterval { get; init; } = TimeSpan.FromSeconds(10);
 
     public int MaxFrameBytes { get; init; } = 16 << 20;
@@ -96,7 +99,7 @@ public sealed class FleetLink
     private readonly INodeLog _log;
     private volatile RpcSession<LinkContext>? _session;
     private volatile bool _stopped;
-    private static readonly TimeSpan s_connectTimeout = TimeSpan.FromSeconds(20);
+
     private static readonly TimeSpan s_tcpTimeout = TimeSpan.FromSeconds(4);
     private int _failedConnects;
 
@@ -179,7 +182,7 @@ public sealed class FleetLink
         using var handler = new SocketsHttpHandler { ConnectCallback = (context, token) => ConnectTcpAsync(context, attempt, token) };
         using var invoker = new HttpMessageInvoker(handler, disposeHandler: false);
         using CancellationTokenSource timeout = CancellationTokenSource.CreateLinkedTokenSource(ct);
-        timeout.CancelAfter(s_connectTimeout);
+        timeout.CancelAfter(_options.ConnectTimeout);
         try
         {
             await socket.ConnectAsync(uri, invoker, timeout.Token);
@@ -233,7 +236,7 @@ public sealed class FleetLink
         socket.Options.KeepAliveInterval = TimeSpan.FromSeconds(15);
         socket.Options.KeepAliveTimeout = TimeSpan.FromSeconds(20); // 对端 20 秒没有回 Pong 就判定连接已死
         var builder = new UriBuilder(_options.Server) { Scheme = _options.Server.Scheme == "https" ? "wss" : "ws", Path = RpcPath };
-        await socket.ConnectAsync(builder.Uri, ct);
+        await ConnectAsync(socket, builder.Uri, ct);
         await using var transport = new SecureTransport(new WsTransport(socket, _options.MaxFrameBytes));
 
         string? failure = await AuthenticateAsync(transport, ct);