Add NuGet test project for validating deployment package

- Include `NullOpsDevs.Libssh.NuGetTest` in solution.
- Add basic program to test SSH connection, authentication, and command execution.
- Reference `NullOpsDevs.LibSsh` version `1.0.0-deploy-test`.
- Target .NET 9.0 framework for NuGet test project.

Author: 0x25CBFC4F

NullOpsDevs.LibSsh.slnx

@@ -3,6 +3,7 @@
     <File Path=".github\workflows\test.yml" />
     <File Path=".github\workflows\publish.yml" />
   </Folder>
+  <Project Path="NullOpsDevs.Libssh.NuGetTest\NullOpsDevs.Libssh.NuGetTest.csproj" Type="Classic C#" />
   <Project Path="NullOpsDevs.LibSsh.Test\NullOpsDevs.LibSsh.Test.csproj" Type="Classic C#" />
   <Project Path="NullOpsDevs.LibSsh/NullOpsDevs.LibSsh.csproj" />
 </Solution>

NullOpsDevs.Libssh.NuGetTest/NullOpsDevs.Libssh.NuGetTest.csproj

@@ -0,0 +1,14 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <OutputType>Exe</OutputType>
+        <TargetFramework>net9.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+    </PropertyGroup>
+
+    <ItemGroup>
+      <PackageReference Include="NullOpsDevs.LibSsh" Version="1.0.0-deploy-test" />
+    </ItemGroup>
+
+</Project>

NullOpsDevs.Libssh.NuGetTest/Program.cs

@@ -0,0 +1,8 @@
+using NullOpsDevs.LibSsh.Core;
+using NullOpsDevs.LibSsh.Credentials;
+
+var ssh = new SshSession();
+ssh.Connect("localhost", 2222);
+ssh.Authenticate(SshCredential.FromPassword("user", "12345"));
+
+Console.WriteLine(ssh.ExecuteCommand("ls").Stdout);