refactor: rename Api project to Web

- HrynCo.NotificationService.Api -> HrynCo.NotificationService.Web
- HrynCo.NotificationService.Api.IntegrationTests -> HrynCo.NotificationService.Web.IntegrationTests
- Updated slnx, docker-compose, project references, and namespaces
- Project serves both REST API and admin UI

Ref: IT-628

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

HrynCo.NotificationService.Web/Program.cs

@@ -0,0 +1,34 @@
+using HrynCo.NotificationService.Web;
+using HrynCo.NotificationService.DAL.EF;
+using HrynCo.NotificationService.Services;
+using Scalar.AspNetCore;
+
+var builder = WebApplication.CreateBuilder(args);
+
+builder.AddSerilog();
+
+var appSettings = builder.Configuration
+    .GetSection(AppSettings.SectionName)
+    .Get<AppSettings>() ?? throw new InvalidOperationException("App settings are not configured.");
+
+builder.Services.AddSingleton(appSettings);
+builder.Services.AddOpenApi();
+builder.Services.AddControllers();
+builder.Services.AddNotificationDataAccess(appSettings.ConnectionString);
+builder.Services.AddNotificationServices();
+
+var app = builder.Build();
+
+if (app.Environment.IsDevelopment())
+{
+    app.MapOpenApi();
+    app.MapScalarApiReference(options =>
+    {
+        options.Title = "HrynCo Notification Service";
+        options.Theme = ScalarTheme.DeepSpace;
+    });
+}
+
+app.UseHttpsRedirection();
+app.MapControllers();
+app.Run();