Add unit tests for Router configuration and transport layers

- Implemented tests for RouterConfig, RoutingOptions, StaticInstanceConfig, and RouterConfigOptions to ensure default values are set correctly.
- Added tests for RouterConfigProvider to validate configurations and ensure defaults are returned when no file is specified.
- Created tests for ConfigValidationResult to check success and error scenarios.
- Developed tests for ServiceCollectionExtensions to verify service registration for RouterConfig.
- Introduced UdpTransportTests to validate serialization, connection, request-response, and error handling in UDP transport.
- Added scripts for signing authority gaps and hashing DevPortal SDK snippets.

src/Gateway/StellaOps.Gateway.WebService/Program.cs

@@ -1,12 +1,19 @@
+using StellaOps.Gateway.WebService;
+
 var builder = WebApplication.CreateBuilder(args);
 
-// Placeholder: Gateway services will be registered here in later sprints
+// Register gateway routing services
+builder.Services.AddGatewayRouting(builder.Configuration);
 
 var app = builder.Build();
 
-// Placeholder: Middleware pipeline will be configured here in later sprints
+// Health check endpoint (not routed through gateway middleware)
 app.MapGet("/health", () => Results.Ok(new { status = "healthy" }));
 
+// Gateway router middleware pipeline
+// All other requests are routed through the gateway
+app.UseGatewayRouter();
+
 app.Run();
 
 // Make Program class accessible for integration tests