Add custom app icon: contact silhouette with sync arrows

Generated programmatically, no external ICO file needed.
Blue rounded square with white person silhouette and green/yellow
sync arrows. Used for main window title bar and system tray.

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

src/StarfaceOutlookSync/UI/MainForm.cs

@@ -62,6 +62,7 @@ namespace StarfaceOutlookSync.UI
             MinimumSize = new Size(500, 350);
             StartPosition = FormStartPosition.CenterScreen;
             Font = new Font("Segoe UI", 9);
+            Icon = AppIcon.GetIcon();
 
             // Profil-Liste
             _profileList = new ListView
@@ -128,7 +129,7 @@ namespace StarfaceOutlookSync.UI
             _trayIcon = new NotifyIcon
             {
                 Text = "Starface Kontakt-Sync",
-                Icon = SystemIcons.Application,
+                Icon = AppIcon.GetSmallIcon(),
                 ContextMenuStrip = _trayMenu,
                 Visible = true
             };