feat(Program): make Quartz cron schedule configurable via appsettings

- Replaced hardcoded cron expression with configuration-based `Worker:CronExpression`.
- Throws descriptive exception if cron expression is missing.
- Keeps previous worker and DB context setup unchanged.

EnvelopeGenerator.Finalizer/Program.cs

@@ -42,18 +42,23 @@ try
         var jobKey = new JobKey(name);
         q.AddJob<Worker>(opts => opts.WithIdentity(jobKey));
 
+        var expression = config[nameof(Worker) + ":CronExpression"];
+        if (string.IsNullOrWhiteSpace(expression))
+            throw new InvalidOperationException(
+             "Cron expression for the Worker job is not configured. " +
+             "Please provide a valid cron schedule in the configuration under " +
+             $"'{nameof(Worker)}:CronExpression'.");
+
         q.AddTrigger(opts => opts
             .ForJob(jobKey)
             .WithIdentity(name + "-trigger")
-            .WithCronSchedule("* * * * * ?"));
+            .WithCronSchedule(expression));
     });
 
     builder.Services.AddQuartzHostedService(opt =>
     {
         opt.WaitForJobsToComplete = true;
     });
-
-    builder.Services.Configure<WorkerOptions>(config.GetSection("Worker"));
     #endregion
 
     #region Add DB Context, EG Inf. and Services