Enhance service configuration and DI setup

Added `EnvelopeGenerator.WebUI.Client.Services` to the using directives. Registered `IHttpContextAccessor` to access HTTP context for request-specific information. Modified `HttpClient` setup to dynamically set the base address using the current request's host. Introduced several business services (`DocumentService`, `AuthService`, `AnnotationService`, `EnvelopeReceiverService`, `SignatureService`, `SignatureCacheService`, `AppVersionService`) to the service collection, indicating new features. Maintained existing YARP configuration. Noted the importance of DevExpress services for `DxPdfViewer`.

EnvelopeGenerator.WebUI/EnvelopeGenerator.WebUI/Program.cs

@@ -1,5 +1,6 @@
 using EnvelopeGenerator.WebUI.Components;
 using DevExpress.Blazor;
+using EnvelopeGenerator.WebUI.Client.Services;
 
 var builder = WebApplication.CreateBuilder(args);
 
@@ -12,12 +13,31 @@ builder.Services.AddRazorComponents()
     .AddInteractiveWebAssemblyComponents();
 
 // HttpClient for server-side components (e.g., MainLayout with FontLoader)
+builder.Services.AddHttpContextAccessor();
 builder.Services.AddScoped<HttpClient>(sp => {
-    var httpClientFactory = sp.GetRequiredService<IHttpClientFactory>();
+    var httpContextAccessor = sp.GetRequiredService<IHttpContextAccessor>();
-    return httpClientFactory.CreateClient();
+    var request = httpContextAccessor.HttpContext?.Request;
+    
+    var httpClient = sp.GetRequiredService<IHttpClientFactory>().CreateClient();
+    
+    if (request != null) {
+        // Set base address to current host (e.g., https://localhost:5131)
+        httpClient.BaseAddress = new Uri($"{request.Scheme}://{request.Host}");
+    }
+    
+    return httpClient;
 });
 builder.Services.AddHttpClient();
 
+// Business Services
+builder.Services.AddScoped<DocumentService>();
+builder.Services.AddScoped<AuthService>();
+builder.Services.AddScoped<AnnotationService>();
+builder.Services.AddScoped<EnvelopeReceiverService>();
+builder.Services.AddScoped<SignatureService>();
+builder.Services.AddScoped<SignatureCacheService>();
+builder.Services.AddSingleton<AppVersionService>();
+
 // YARP Reverse Proxy
 builder.Services.AddReverseProxy()
     .LoadFromConfig(builder.Configuration.GetSection("ReverseProxy"));