Enhance envelope creation and update functionality

Added new optional properties to `CreateEnvelopeCommand` for detailed configuration, including `EnvelopeId`, `Language`, `UseAccessCode`, and expiration settings. Introduced `ResolveEnvelopeSettingsAsync` to centralize settings resolution logic. Updated `CreateEnvelopeCommandHandler` to handle new properties and improve envelope creation/update flow. Added `EnvelopeSettings` record for structured settings management. Enhanced SQL update logic with `UseSQLExecutor` support. Improved handling of language resolution, reminders, and expiration rules.

EnvelopeGenerator.Application/Envelopes/Commands/CreateEnvelopeCommand.cs

@@ -12,8 +12,66 @@ namespace EnvelopeGenerator.Application.Envelopes.Commands;
 /// </summary>
 public record CreateEnvelopeCommand : IRequest<EnvelopeDto?>
 {
+    /// <summary>
+    /// Optionale Umschlag-ID fuer Aktualisierungsvorgaenge.
+    /// </summary>
     public int? EnvelopeId { get; init; }
 
+    /// <summary>
+    /// Kennung des ausgewaehlten Umschlagtyps (Vorlage).
+    /// </summary>
+    public int? EnvelopeTypeId { get; set; }
+
+    /// <summary>
+    /// Sprachcode fuer Umschlaginhalt und Benachrichtigungen.
+    /// </summary>
+    public string? Language { get; set; }
+
+    /// <summary>
+    /// Gibt an, ob der Zugriffscode fuer Empfaenger aktiviert ist.
+    /// </summary>
+    public bool? UseAccessCode { get; set; }
+
+    /// <summary>
+    /// Zertifizierungstyp fuer den Signaturprozess.
+    /// </summary>
+    public int? CertificationType { get; set; }
+
+    /// <summary>
+    /// Finale E-Mail-Einstellung fuer den Ersteller.
+    /// </summary>
+    public int? FinalEmailToCreator { get; set; }
+
+    /// <summary>
+    /// Finale E-Mail-Einstellung fuer die Empfaenger.
+    /// </summary>
+    public int? FinalEmailToReceivers { get; set; }
+
+    /// <summary>
+    /// Gibt an, ob Erinnerungs-E-Mails aktiviert sind.
+    /// </summary>
+    public bool? SendReminderEmails { get; set; }
+
+    /// <summary>
+    /// Anzahl der Tage bis zur ersten Erinnerung.
+    /// </summary>
+    public int? FirstReminderDays { get; set; }
+
+    /// <summary>
+    /// Intervall in Tagen zwischen Erinnerungs-E-Mails.
+    /// </summary>
+    public int? ReminderIntervalDays { get; set; }
+
+    /// <summary>
+    /// Anzahl der Tage bis zum Ablauf des Umschlags.
+    /// </summary>
+    public int? ExpiresWhenDays { get; set; }
+
+    /// <summary>
+    /// Anzahl der Tage vor Ablauf, ab denen gewarnt wird.
+    /// </summary>
+    public int? ExpiresWarningWhenDays { get; set; }
+
     /// <summary>
     /// Der Titel des Umschlags. Dies ist ein Pflichtfeld.
     /// </summary>
@@ -29,10 +87,19 @@ public record CreateEnvelopeCommand : IRequest<EnvelopeDto?>
     /// </summary>
     public bool TFAEnabled { get; set; } = false;
 
+    /// <summary>
+    /// Gibt an, ob der Umschlag nach dem Speichern sofort versendet werden soll.
+    /// </summary>
     public bool Send { get; init; }
 
+    /// <summary>
+    /// Optionaler PDF-Dokumentinhalt als Base64.
+    /// </summary>
     public CreateEnvelopeDocumentDto? Document { get; init; }
 
+    /// <summary>
+    /// Empfaengerliste inklusive optionaler Signaturfeld-Koordinaten.
+    /// </summary>
     public List<CreateEnvelopeReceiverDto> Receivers { get; init; } = new();
 
     /// <summary>