Rewrite as standalone C# WinForms app

Replace the Office Web Add-in with a native Windows application.
The web add-in required Exchange/M365 for registration which is
not available in all customer environments (standalone Office,
POP/IMAP only).

The new app:
- Uses COM Interop to access Outlook contacts directly
- Communicates with Starface REST API (accepts self-signed certs)
- Runs as System Tray app with optional auto-sync
- Profile-based config stored in %AppData%
- No webserver, no certificates, no Exchange, no M365 needed
- Inno Setup installer for clean MSI-style deployment
- Works with any Outlook version (Classic and New)

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

src/StarfaceOutlookSync/Program.cs

@@ -0,0 +1,33 @@
+using System;
+using System.Threading;
+using System.Windows.Forms;
+
+namespace StarfaceOutlookSync
+{
+    static class Program
+    {
+        private static Mutex _mutex;
+
+        [STAThread]
+        static void Main()
+        {
+            // Nur eine Instanz erlauben
+            const string mutexName = "StarfaceOutlookSync_SingleInstance";
+            _mutex = new Mutex(true, mutexName, out bool createdNew);
+
+            if (!createdNew)
+            {
+                MessageBox.Show(
+                    "Starface Outlook Sync laeuft bereits.",
+                    "Starface Outlook Sync",
+                    MessageBoxButtons.OK,
+                    MessageBoxIcon.Information);
+                return;
+            }
+
+            Application.EnableVisualStyles();
+            Application.SetCompatibleTextRenderingDefault(false);
+            Application.Run(new UI.MainForm());
+        }
+    }
+}