Add option to suppress Outlook security prompt

New setting "Outlook-Sicherheitsabfrage automatisch erlauben"
sets registry keys under HKCU\Policies\Microsoft\Office\16.0\
Outlook\Security to auto-approve Object Model Guard prompts.

Applied at app startup and when saving settings. Disabling the
option removes the registry values (back to Outlook default).
Works with all Outlook versions (2016-2024, same registry path).
No admin rights needed (HKCU).

Outlook must be restarted after changing this setting.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/StarfaceOutlookSync/UI/MainForm.cs

@@ -31,8 +31,10 @@ namespace StarfaceOutlookSync.UI
             SetupAutoSync();
             RefreshProfileList();
 
-            // Minimiert starten falls in Einstellungen aktiviert
+            // Einstellungen laden und anwenden
             var settings = UserSettings.Load();
+            settings.ApplyOutlookSecuritySetting();
+
             if (settings.StartMinimized)
             {
                 WindowState = FormWindowState.Minimized;