Initial commit: FieldLogger MAUI app with Maglink BLE support

Added Maglink RTK GNSS receiver integration with correct BLE UUIDs and device name filtering (ML-* prefix).

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

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

FieldLogger/App.xaml.cs

@@ -0,0 +1,14 @@
+namespace FieldLogger;
+
+public partial class App : Application
+{
+	public App()
+	{
+		InitializeComponent();
+	}
+
+	protected override Window CreateWindow(IActivationState? activationState)
+	{
+		return new Window(new AppShell());
+	}
+}