Add project files.

Gateway/Program.cs

@@ -0,0 +1,80 @@
+using Gateway.Data;
+using Gateway.ProviderClients;
+using Gateway.Security;
+using Gateway.Services;
+
+var builder = WebApplication.CreateBuilder(args);
+
+// --------------------
+// Container-friendly HTTP binding
+// --------------------
+var port = Environment.GetEnvironmentVariable("PORT") ?? "8080";
+builder.WebHost.UseUrls($"http://0.0.0.0:{port}");
+
+// --------------------
+// Services
+// --------------------
+builder.Services.AddControllers();
+builder.Services.AddEndpointsApiExplorer();
+builder.Services.AddSwaggerGen();
+
+// Data & business services
+builder.Services.AddScoped<SqlService>();
+builder.Services.AddScoped<ExecutionService>();
+
+// Authentication context (scoped - one per request)
+builder.Services.AddScoped<ClientContext>();
+
+// Provider clients
+builder.Services.AddHttpClient<GoogleProviderClient>(client =>
+{
+    var baseUrl = builder.Configuration["Provider:Google:BaseUrl"]
+        ?? Environment.GetEnvironmentVariable("GOOGLE_PROVIDER_URL")
+        ?? "";
+    if (!string.IsNullOrWhiteSpace(baseUrl))
+        client.BaseAddress = new Uri(baseUrl.EndsWith("/") ? baseUrl : baseUrl + "/");
+});
+
+// HTTP client factory for ExecutionService
+builder.Services.AddHttpClient();
+
+var app = builder.Build();
+
+// --------------------
+// Middleware pipeline
+// --------------------
+
+// Swagger (enabled for all environments in containers)
+app.UseSwagger();
+app.UseSwaggerUI();
+
+// Health check endpoint (before auth & logging)
+app.MapGet("/health", () => Results.Ok(new
+{
+    ok = true,
+    service = "Gateway",
+    timestamp = DateTimeOffset.UtcNow
+}));
+
+// Root endpoint
+app.MapGet("/", () => Results.Ok(new
+{
+    service = "Gateway API",
+    version = "1.0.0",
+    status = "Application Gateway running"
+}));
+
+// Access logging middleware (captures all requests)
+// Placed BEFORE auth so we log even failed auth attempts
+app.UseAccessLogging();
+
+// Client authentication middleware (multi-provider)
+// - Validates JWTs from Microsoft, Google, etc.
+// - Accepts X-Dev-ClientId header (development)
+app.UseMiddleware<MultiProviderAuthMiddleware>();
+
+// Standard middleware
+app.UseAuthorization();
+app.MapControllers();
+
+app.Run();