[Add]: Add SignClient Plugin

src/Neo.CLI/CLI/MainService.Wallet.cs

@@ -73,7 +73,7 @@ private void OnCloseWalletCommand()
 
             if (CurrentWallet is not null)
             {
-                SignerFactory.UnregisterSigner(CurrentWallet.Name);
+                SignerManager.UnregisterSigner(CurrentWallet.Name);
             }
 
             CurrentWallet = null;

src/Neo.CLI/CLI/MainService.cs

@@ -161,7 +161,7 @@ public void CreateWallet(string path, string password, bool createDefaultAccount
             wallet.Save();
 
             CurrentWallet = wallet;
-            SignerFactory.RegisterSigner(wallet.Name, wallet);
+            SignerManager.RegisterSigner(wallet.Name, wallet);
         }
 
         private bool NoWallet()
@@ -296,10 +296,10 @@ public void OpenWallet(string path, string password)
                 throw new FileNotFoundException($"Wallet file \"{path}\" not found.");
             }
 
-            if (CurrentWallet is not null) SignerFactory.UnregisterSigner(CurrentWallet.Name);
+            if (CurrentWallet is not null) SignerManager.UnregisterSigner(CurrentWallet.Name);
 
             CurrentWallet = Wallet.Open(path, password, NeoSystem.Settings) ?? throw new NotSupportedException();
-            SignerFactory.RegisterSigner(CurrentWallet.Name, CurrentWallet);
+            SignerManager.RegisterSigner(CurrentWallet.Name, CurrentWallet);
         }
 
         public async void Start(CommandLineOptions options)

src/Neo/Sign/ISigner.cs

@@ -21,7 +21,7 @@ namespace Neo.Sign
     public interface ISigner
     {
         /// <summary>
-        /// Signs the <see cref="ContractParametersContext"/> with the wallet.
+        /// Signs the <see cref="ContractParametersContext"/> with the signer.
         /// </summary>
         /// <param name="context">The <see cref="ContractParametersContext"/> to be used.</param>
         /// <returns>

src/Neo/Sign/SignException.cs

@@ -22,6 +22,7 @@ public class SignException : Exception
         /// Initializes a new instance of the <see cref="SignException"/> class.
         /// </summary>
         /// <param name="message">The message that describes the error.</param>
-        public SignException(string message) : base(message) { }
+        /// <param name="cause">The cause of the exception.</param>
+        public SignException(string message, Exception cause = null) : base(message, cause) { }
     }
 }

src/Neo/Sign/SignerFactory.cs → src/Neo/Sign/SignerManager.cs

@@ -1,6 +1,6 @@
 // Copyright (C) 2015-2025 The Neo Project.
 //
-// SignerFactory.cs file belongs to the neo project and is free
+// SignerManager.cs file belongs to the neo project and is free
 // software distributed under the MIT software license, see the
 // accompanying file LICENSE in the main directory of the
 // repository or http://www.opensource.org/licenses/mit-license.php
@@ -15,7 +15,7 @@
 
 namespace Neo.Sign
 {
-    public static class SignerFactory
+    public static class SignerManager
     {
         private static readonly ConcurrentDictionary<string, ISigner> s_signers = new();
 

src/Plugins/DBFTPlugin/DBFTPlugin.cs

@@ -87,7 +87,7 @@ void IWalletChangedHandler.IWalletProvider_WalletChanged_Handler(object sender,
         [ConsoleCommand("start consensus", Category = "Consensus", Description = "Start consensus service (dBFT)")]
         private void OnStart(string signerName = "")
         {
-            var signer = SignerFactory.GetSignerOrDefault(signerName);
+            var signer = SignerManager.GetSignerOrDefault(signerName);
             Start(signer ?? walletProvider.GetWallet());
         }
 

src/Plugins/SignClient/Settings.cs

@@ -0,0 +1,57 @@
+// Copyright (C) 2015-2025 The Neo Project.
+//
+// Settings.cs file belongs to the neo project and is free
+// software distributed under the MIT software license, see the
+// accompanying file LICENSE in the main directory of the
+// repository or http://www.opensource.org/licenses/mit-license.php
+// for more details.
+//
+// Redistribution and use in source and binary forms with or without
+// modifications are permitted.
+
+using Microsoft.Extensions.Configuration;
+using System.Net;
+
+namespace Neo.Plugins.SignClient
+{
+    public class Settings : PluginSettings
+    {
+        /// <summary>
+        /// Only support local host at present, so host always is "127.0.0.1" or "::1" now.
+        /// </summary>
+        public static readonly string DefaultEndpoint = $"http://{IPAddress.Loopback}:9991";
+        public const string SectionName = "PluginConfiguration";
+
+        /// <summary>
+        /// The name of the sign client(i.e. Signer).
+        /// </summary>
+        public readonly string Name;
+
+        /// <summary>
+        /// The host of the sign client(i.e. Signer).
+        /// </summary>
+        public readonly string Endpoint;
+
+        public Settings(IConfigurationSection section) : base(section)
+        {
+            Name = section.GetValue("Name", "SignClient");
+            Endpoint = section.GetValue("Endpoint", DefaultEndpoint);
+        }
+
+        public static Settings Default
+        {
+            get
+            {
+                var section = new ConfigurationBuilder()
+                    .AddInMemoryCollection(new Dictionary<string, string?>
+                    {
+                        [SectionName + ":Name"] = "SignClient",
+                        [SectionName + ":Endpoint"] = DefaultEndpoint
+                    })
+                    .Build()
+                    .GetSection(SectionName);
+                return new Settings(section);
+            }
+        }
+    }
+}