Mark CommandManager as obsolete; add warning suppression

Updated `CommandManager` to mark the `_envelopeReceiverService` field and its constructor as obsolete, recommending the use of `MediatR`. Added a new obsolete property `EnvelopeReceiver` for accessing the service. In `Program.cs`, added warning suppression for the obsolete member during command manager runner registration.

EnvelopeGenerator.Terminal/CommandManager.cs

@@ -13,9 +13,11 @@ public class CommandManager
     {
         WriteIndented = true
     };
+    [Obsolete("Use MediatR")]
     private readonly IEnvelopeReceiverService _envelopeReceiverService;
     private readonly IMediator _mediator;
 
+    [Obsolete("Use MediatR")]
     public CommandManager(IEnvelopeReceiverService envelopeReceiverService, IMediator mediator)
     {
         _envelopeReceiverService = envelopeReceiverService;
@@ -29,6 +31,7 @@ public class CommandManager
             Console.WriteLine($"v{Assembly.GetExecutingAssembly().GetName().Version}");
     }
 
+    [Obsolete("Use MediatR")]
     [Subcommand]
     public IEnvelopeReceiverService EnvelopeReceiver => _envelopeReceiverService;
 

EnvelopeGenerator.Terminal/Program.cs

@@ -15,7 +15,9 @@ public class Program
 
         var config = builder.Configuration;
 
+#pragma warning disable CS0618 // Type or member is obsolete
         builder.Services.AddCommandManagerRunner(config);
+#pragma warning restore CS0618 // Type or member is obsolete
 
         var app = builder.Build();