Add ADB wrapper (adb CLI)

[rmarinho]

Summary

Add AdbRunner class to Xamarin.Android.Tools.AndroidSdk to wrap adb CLI operations for device management.

Background

The MAUI DevTools CLI and IDE extensions need to list connected devices, start/stop the ADB server, and query device state. This functionality should live in the shared android-tools package.

Reference implementation exists in android-platform-support (internal) Mono.AndroidTools.Adb.

Proposed API Surface

`csharp
public class AdbRunner
{
Task<IReadOnlyList> GetDevicesAsync(CancellationToken ct = default);
Task StartServerAsync(CancellationToken ct = default);
Task KillServerAsync(CancellationToken ct = default);
Task WaitForDeviceAsync(string serial, CancellationToken ct = default);
}

public record AndroidDeviceInfo(string Serial, DeviceState State, string? Model, string? Product, TransportType Transport);
public enum DeviceState { Unknown, Offline, Device, NoDevice, Recovery, Sideload, Unauthorized }
public enum TransportType { Unknown, Usb, Emulator }
`

Consumer

• MAUI DevTools CLI (maui android devices) — see MAUI DevTools Spec PR
• VS/VS Code extensions for device picker

Related

• Add SDK bootstrap and sdkmanager wrapper (move from android-platform-support) #271 (SDK bootstrap)
• MAUI DevTools spec §6.8: Shared Libraries & Code Reuse