Replace Dell logo with Material Design monitor icon

- Add white monitor icon from Google Material Icons (desktop_windows)
- Works with Windows light/dark mode (white icon auto-inverts)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

DellMonitorControl/App.xaml

@@ -6,7 +6,7 @@
              Startup="Application_Startup">
     <Application.Resources>
         <tb:TaskbarIcon x:Key="TrayIcon"
-                        IconSource="/DellLogo.ico"
+                        IconSource="/MonitorIcon.ico"
                         ToolTipText="Monitor Control"/>
     </Application.Resources>
 </Application>

DellMonitorControl/DellMonitorControl.csproj

@@ -27,10 +27,12 @@
 
 	<ItemGroup>
 	  <None Remove="DellLogo.ico" />
+	  <None Remove="MonitorIcon.ico" />
 	</ItemGroup>
 
 	<ItemGroup>
 	  <Resource Include="DellLogo.ico" />
+	  <Resource Include="MonitorIcon.ico" />
 	</ItemGroup>
 
 	<ItemGroup>