feat: add Aspire dashboard OTEL workflow

Add OTLP export wiring for the sidecar and dev scripts to launch the standalone Aspire Dashboard during development.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

sidecar/src/Aryx.AgentHost/Program.cs

@@ -1,4 +1,5 @@
 using Aryx.AgentHost.Services;
+using OpenTelemetry.Trace;
 
 if (!args.Contains("--stdio", StringComparer.Ordinal))
 {
@@ -6,5 +7,7 @@ if (!args.Contains("--stdio", StringComparer.Ordinal))
     return;
 }
 
+using TracerProvider? tracerProvider = OpenTelemetrySetup.CreateTracerProviderFromEnvironment();
+
 SidecarProtocolHost host = new();
 await host.RunAsync(Console.In, Console.Out, CancellationToken.None);