Add "Dubletten zusammenfuehren" (merge duplicates) per profile

Neuer Button "Dubletten" im Hauptfenster fuehrt doppelte Kontakte fuer das
ausgewaehlte Profil zusammen - je Seite (Telefonanlage + Outlook) getrennt.

- Matching in ContactMatcher extrahiert (Sync UND Dedupe nutzen exakt dieselbe
  Erkennung).
- ContactMerger.FillEmptyInto / FilledFieldCount: leere Felder des Gewinners
  auffuellen (kein Datenverlust), Gewinner-Wahl nach Zuordnung/Vollstaendigkeit.
- DedupeService: Analyse (Vorschau) + Ausfuehrung (Merge, Loeschen der
  Dubletten, Bereinigen verwaister Zuordnungen).
- SyncCoordinator.RunExclusiveAsync: Dedupe laeuft unter demselben Guard +
  Lock-Datei wie ein Sync (nie gleichzeitig; kein Konflikt zwischen Clients).
- DedupeForm: Vorschau mit optionaler Detailliste, Bestaetigung, Live-Log;
  danach Hinweis, einmal zu synchronisieren.
- MainForm: Button "Dubletten" (Profil-Auswahl noetig), Fenster verbreitert.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/StarfaceOutlookSync/UI/DedupeForm.cs

@@ -0,0 +1,192 @@
+using System;
+using System.Drawing;
+using System.Threading.Tasks;
+using System.Windows.Forms;
+using StarfaceOutlookSync.Models;
+using StarfaceOutlookSync.Services;
+
+namespace StarfaceOutlookSync.UI
+{
+    /// <summary>
+    /// Dialog zum Zusammenfuehren doppelter Kontakte fuer EIN Profil.
+    /// Analysiert zuerst (Vorschau), fuehrt nach Bestaetigung unter derselben
+    /// Sperre wie ein Sync zusammen.
+    /// </summary>
+    public class DedupeForm : Form
+    {
+        private readonly SyncProfile _profile;
+        private readonly DedupeService _dedupe = new DedupeService();
+        private readonly SyncCoordinator _coordinator = new SyncCoordinator();
+
+        private Label _lblInfo, _lblSummary;
+        private CheckBox _chkDetail;
+        private TextBox _txtLog;
+        private Button _btnStart, _btnClose;
+
+        private DedupeService.DedupePlan _plan;
+        private bool _busy;
+
+        public DedupeForm(SyncProfile profile)
+        {
+            _profile = profile;
+            _dedupe.OnProgress += AppendLog;
+            InitializeComponent();
+            Load += async (s, e) => await Analyze();
+        }
+
+        private void InitializeComponent()
+        {
+            Text = $"Dubletten zusammenfuehren - {_profile.Name}";
+            Size = new Size(640, 500);
+            StartPosition = FormStartPosition.CenterParent;
+            Font = new Font("Segoe UI", 9);
+            MinimizeBox = false;
+
+            _lblInfo = new Label
+            {
+                Text = $"Profil: {_profile.Name}  ({_profile.Connection.System} <-> {_profile.OutlookFolderName})",
+                Left = 12, Top = 12, Width = 600, Height = 20
+            };
+
+            _lblSummary = new Label
+            {
+                Text = "Analysiere...",
+                Left = 12, Top = 36, Width = 600, Height = 40, ForeColor = Color.DimGray
+            };
+
+            _chkDetail = new CheckBox
+            {
+                Text = "Detailvorschau anzeigen (welche Kontakte zusammengefuehrt werden)",
+                Left = 12, Top = 80, AutoSize = true, Enabled = false
+            };
+            _chkDetail.CheckedChanged += (s, e) => { if (_chkDetail.Checked) RenderDetail(); };
+
+            _txtLog = new TextBox
+            {
+                Left = 12, Top = 108, Width = 604, Height = 300,
+                Multiline = true, ReadOnly = true, ScrollBars = ScrollBars.Both, WordWrap = false,
+                BackColor = Color.FromArgb(30, 30, 30), ForeColor = Color.FromArgb(212, 212, 212),
+                Font = new Font("Consolas", 9),
+                Anchor = AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right | AnchorStyles.Bottom
+            };
+
+            _btnStart = new Button
+            {
+                Text = "Zusammenfuehren starten", Left = 12, Top = 420, Width = 190, Height = 30,
+                Enabled = false, Anchor = AnchorStyles.Bottom | AnchorStyles.Left
+            };
+            _btnStart.Click += async (s, e) => await Execute();
+
+            _btnClose = new Button
+            {
+                Text = "Schliessen", Left = 526, Top = 420, Width = 90, Height = 30,
+                DialogResult = DialogResult.Cancel, Anchor = AnchorStyles.Bottom | AnchorStyles.Right
+            };
+
+            Controls.AddRange(new Control[] { _lblInfo, _lblSummary, _chkDetail, _txtLog, _btnStart, _btnClose });
+            CancelButton = _btnClose;
+        }
+
+        private void AppendLog(string message)
+        {
+            if (InvokeRequired) { Invoke(new Action(() => AppendLog(message))); return; }
+            _txtLog.AppendText(message + "\r\n");
+        }
+
+        private async Task Analyze()
+        {
+            _busy = true;
+            _btnStart.Enabled = false;
+            try
+            {
+                _plan = await Task.Run(() => _dedupe.AnalyzeAsync(_profile));
+
+                var s = $"Telefonanlage: {_plan.RemoteGroups.Count} Gruppe(n) mit Dubletten, {_plan.RemoteDeletions} Kontakt(e) werden zusammengefuehrt.\r\n" +
+                        $"Outlook: {_plan.OutlookGroups.Count} Gruppe(n) mit Dubletten, {_plan.OutlookDeletions} Kontakt(e) werden zusammengefuehrt.";
+                _lblSummary.Text = _plan.HasWork ? s : "Keine Dubletten gefunden. Alles sauber. ✓";
+                _lblSummary.ForeColor = _plan.HasWork ? Color.OrangeRed : Color.Green;
+
+                _chkDetail.Enabled = _plan.HasWork;
+                _btnStart.Enabled = _plan.HasWork;
+                if (_chkDetail.Checked) RenderDetail();
+            }
+            catch (Exception ex)
+            {
+                _lblSummary.Text = "Analyse fehlgeschlagen: " + ex.Message;
+                _lblSummary.ForeColor = Color.Red;
+                AppendLog("FEHLER: " + ex.Message);
+            }
+            finally { _busy = false; }
+        }
+
+        private void RenderDetail()
+        {
+            if (_plan == null) return;
+            AppendLog("");
+            AppendLog("=== Vorschau: Telefonanlage ===");
+            foreach (var g in _plan.RemoteGroups)
+                AppendLog($"  Behalten: '{g.Survivor.DisplayName}'  <=  {g.Duplicates.Count} Dublette(n)");
+            AppendLog("=== Vorschau: Outlook ===");
+            foreach (var g in _plan.OutlookGroups)
+                AppendLog($"  Behalten: '{g.Survivor.DisplayName}'  <=  {g.Duplicates.Count} Dublette(n)");
+            AppendLog("");
+        }
+
+        private async Task Execute()
+        {
+            if (_busy || _plan == null || !_plan.HasWork) return;
+
+            var confirm = MessageBox.Show(this,
+                $"Jetzt zusammenfuehren?\n\n" +
+                $"Telefonanlage: {_plan.RemoteDeletions} Dublette(n) werden geloescht.\n" +
+                $"Outlook: {_plan.OutlookDeletions} Dublette(n) werden geloescht.\n\n" +
+                $"Die Daten der Dubletten werden vorher in den behaltenen Kontakt uebernommen (leere Felder aufgefuellt).\n" +
+                $"Danach bitte einmal synchronisieren.",
+                "Dubletten zusammenfuehren", MessageBoxButtons.YesNo, MessageBoxIcon.Warning);
+            if (confirm != DialogResult.Yes) return;
+
+            _busy = true;
+            _btnStart.Enabled = false;
+            _btnClose.Enabled = false;
+            AppendLog("Starte Zusammenfuehrung...");
+            Logger.Log($"Dubletten-Zusammenfuehrung gestartet: Profil '{_profile.Name}'");
+
+            try
+            {
+                DedupeService.DedupeReport report = null;
+                bool ran = await _coordinator.RunExclusiveAsync(
+                    async () => { report = await Task.Run(() => _dedupe.ExecuteAsync(_profile)); },
+                    status: AppendLog);
+
+                if (!ran)
+                {
+                    AppendLog("Abgebrochen (Sync/Aktion laeuft oder anderer Arbeitsplatz aktiv).");
+                }
+                else if (report != null)
+                {
+                    var summary = $"Fertig. Anlage: {report.RemoteMerged} Gruppe(n), {report.RemoteDeleted} geloescht. " +
+                                  $"Outlook: {report.OutlookMerged} Gruppe(n), {report.OutlookDeleted} geloescht. " +
+                                  $"Fehler: {report.Errors}.";
+                    AppendLog(summary);
+                    foreach (var m in report.Messages) AppendLog("  " + m);
+                    AppendLog("Bitte jetzt einmal synchronisieren, damit die Zuordnungen sauber neu aufgebaut werden.");
+                    Logger.Log("Dubletten-Zusammenfuehrung: " + summary);
+                    foreach (var m in report.Messages) Logger.Log("  " + m);
+
+                    _lblSummary.Text = summary + "  ->  Jetzt synchronisieren.";
+                    _lblSummary.ForeColor = report.Errors > 0 ? Color.OrangeRed : Color.Green;
+                }
+            }
+            catch (Exception ex)
+            {
+                AppendLog("FEHLER: " + ex.Message);
+                Logger.Log($"Dubletten-Zusammenfuehrung FEHLER '{_profile.Name}': {ex.Message}");
+            }
+            finally
+            {
+                _busy = false;
+                _btnClose.Enabled = true;
+            }
+        }
+    }
+}

src/StarfaceOutlookSync/UI/MainForm.cs

@@ -19,7 +19,7 @@ namespace StarfaceOutlookSync.UI
         private NotifyIcon _trayIcon;
         private ContextMenuStrip _trayMenu;
         private ListView _profileList;
-        private Button _btnNew, _btnEdit, _btnDelete, _btnSync, _btnReset, _btnSettings, _btnLog, _btnInfo;
+        private Button _btnNew, _btnEdit, _btnDelete, _btnSync, _btnDedupe, _btnReset, _btnSettings, _btnLog, _btnInfo;
         private StatusStrip _statusBar;
         private ToolStripStatusLabel _statusLabel;
         private Timer _autoSyncTimer;
@@ -83,8 +83,8 @@ namespace StarfaceOutlookSync.UI
         private void InitializeComponent()
         {
             Text = "Starface Kontakt-Sync";
-            Size = new Size(830, 450);
-            MinimumSize = new Size(830, 350);
+            Size = new Size(930, 450);
+            MinimumSize = new Size(930, 350);
             StartPosition = FormStartPosition.CenterScreen;
             Font = new Font("Segoe UI", 9);
             Icon = AppIcon.GetIcon();
@@ -126,6 +126,9 @@ namespace StarfaceOutlookSync.UI
             _btnSync = new Button { Text = "Synchronisieren", Width = 110, Height = 30 };
             _btnSync.Click += async (s, e) => await SyncSelectedProfile();
 
+            _btnDedupe = new Button { Text = "Dubletten", Width = 85, Height = 30 };
+            _btnDedupe.Click += (s, e) => ShowDedupe();
+
             _btnReset = new Button { Text = "Sync Reset", Width = 80, Height = 30 };
             _btnReset.Click += (s, e) => ResetSync();
 
@@ -138,7 +141,7 @@ namespace StarfaceOutlookSync.UI
             _btnInfo = new Button { Text = "Info", Width = 50, Height = 30 };
             _btnInfo.Click += (s, e) => ShowAbout();
 
-            buttonPanel.Controls.AddRange(new Control[] { _btnNew, _btnEdit, _btnDelete, _btnSync, _btnReset, _btnSettings, _btnLog, _btnInfo });
+            buttonPanel.Controls.AddRange(new Control[] { _btnNew, _btnEdit, _btnDelete, _btnSync, _btnDedupe, _btnReset, _btnSettings, _btnLog, _btnInfo });
 
             // Statusbar
             _statusBar = new StatusStrip();
@@ -458,6 +461,24 @@ namespace StarfaceOutlookSync.UI
             }
         }
 
+        private void ShowDedupe()
+        {
+            if (_profileList.SelectedItems.Count == 0)
+            {
+                MessageBox.Show("Bitte zuerst ein Profil auswaehlen.", "Dubletten",
+                    MessageBoxButtons.OK, MessageBoxIcon.Information);
+                return;
+            }
+            var profile = _profileList.SelectedItems[0].Tag as SyncProfile;
+            if (profile == null) return;
+
+            using (var form = new DedupeForm(profile))
+            {
+                form.ShowDialog(this);
+            }
+            RefreshProfileList();
+        }
+
         private void ExitApplication()
         {
             _autoSyncTimer?.Stop();