Add Outlook folder browser and user settings

- Replace Outlook folder ComboBox with TextBox + Browse button
  that opens a TreeView-based folder browser dialog
- Add per-user settings stored in %AppData% (not HKLM)
  with option to start minimized (System Tray only)
- Add Settings button to main window
- Settings are per-user, independent of profiles

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

src/StarfaceOutlookSync/UI/MainForm.cs

@@ -18,7 +18,7 @@ namespace StarfaceOutlookSync.UI
         private NotifyIcon _trayIcon;
         private ContextMenuStrip _trayMenu;
         private ListView _profileList;
-        private Button _btnNew, _btnEdit, _btnDelete, _btnSync, _btnInfo;
+        private Button _btnNew, _btnEdit, _btnDelete, _btnSync, _btnSettings, _btnInfo;
         private StatusStrip _statusBar;
         private ToolStripStatusLabel _statusLabel;
         private Timer _autoSyncTimer;
@@ -29,6 +29,30 @@ namespace StarfaceOutlookSync.UI
             SetupTrayIcon();
             SetupAutoSync();
             RefreshProfileList();
+
+            // Minimiert starten falls in Einstellungen aktiviert
+            var settings = UserSettings.Load();
+            if (settings.StartMinimized)
+            {
+                WindowState = FormWindowState.Minimized;
+                ShowInTaskbar = false;
+                Visible = false;
+            }
+        }
+
+        protected override void SetVisibleCore(bool value)
+        {
+            // Beim ersten Anzeigen pruefen ob minimiert gestartet werden soll
+            if (!IsHandleCreated)
+            {
+                var settings = UserSettings.Load();
+                if (settings.StartMinimized)
+                {
+                    CreateHandle();
+                    value = false;
+                }
+            }
+            base.SetVisibleCore(value);
         }
 
         private void InitializeComponent()
@@ -76,10 +100,13 @@ namespace StarfaceOutlookSync.UI
             _btnSync = new Button { Text = "Jetzt synchronisieren", Width = 150, Height = 30 };
             _btnSync.Click += async (s, e) => await SyncSelectedProfile();
 
+            _btnSettings = new Button { Text = "Einstellungen", Width = 100, Height = 30 };
+            _btnSettings.Click += (s, e) => ShowSettings();
+
             _btnInfo = new Button { Text = "Info", Width = 50, Height = 30 };
             _btnInfo.Click += (s, e) => ShowAbout();
 
-            buttonPanel.Controls.AddRange(new Control[] { _btnNew, _btnEdit, _btnDelete, _btnSync, _btnInfo });
+            buttonPanel.Controls.AddRange(new Control[] { _btnNew, _btnEdit, _btnDelete, _btnSync, _btnSettings, _btnInfo });
 
             // Statusbar
             _statusBar = new StatusStrip();
@@ -283,6 +310,14 @@ namespace StarfaceOutlookSync.UI
                 _statusLabel.Text = text;
         }
 
+        private void ShowSettings()
+        {
+            using (var settings = new SettingsForm())
+            {
+                settings.ShowDialog(this);
+            }
+        }
+
         private void ShowAbout()
         {
             using (var about = new AboutForm())