feat(templates): add service language template management

Add normalized service and template catalogs, scoped administration, migration, validation, and regression coverage.

Ref: IT-1601

HrynCo.NotificationService.Web/Program.cs

@@ -29,7 +29,8 @@ app.MapScalarApiReference(options =>
 
 app.UseStaticFiles();
 app.UseHttpsRedirection();
-app.MapGet("/", () => Results.Redirect("/admin/templates"));
+app.MapGet("/", () => Results.Redirect("/admin/services"));
 app.MapControllers();
 app.MapDefaultControllerRoute();
-app.Run();
+app.Run();
+public partial class Program { }