refactor(Program): simplify Quartz job registration and add EnvelopeTaskApiJob

- Replaced manual FinishEnvelopeJob Quartz setup with ScheduleJobDefault extension
- Added scheduling for EnvelopeTaskApiJob
- Updated using directives to include EnvelopeGenerator.Finalizer namespace
- Improved maintainability by removing redundant Quartz configuration logic

EnvelopeGenerator.Finalizer/Job/EnvelopeTaskApiJob.cs

@@ -2,11 +2,11 @@ using Quartz;
 
 namespace EnvelopeGenerator.Finalizer.Job
 {
-    public class EnvelopeTaskApi : IJob
+    public class EnvelopeTaskApiJob : IJob
     {
-        private readonly ILogger<EnvelopeTaskApi> _logger;
+        private readonly ILogger<EnvelopeTaskApiJob> _logger;
 
-        public EnvelopeTaskApi(ILogger<EnvelopeTaskApi> logger)
+        public EnvelopeTaskApiJob(ILogger<EnvelopeTaskApiJob> logger)
         {
             _logger = logger;
         }