Refactor EmulatorRunner per copilot instructions

- Add XML documentation to all public members
- Use 'is not null' instead of '!= null'
- Improve code formatting
- Remove unused variable assignment

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: rmarinho

src/Xamarin.Android.Tools.AndroidSdk/Runners/EmulatorRunner.cs

@@ -17,27 +17,45 @@ public class EmulatorRunner
 {
 readonly Func<string?> getSdkPath;
 
+/// <summary>
+/// Creates a new <see cref="EmulatorRunner"/>.
+/// </summary>
+/// <param name="getSdkPath">Function that returns the Android SDK path.</param>
+/// <exception cref="ArgumentNullException">Thrown when <paramref name="getSdkPath"/> is null.</exception>
 public EmulatorRunner (Func<string?> getSdkPath)
 {
 this.getSdkPath = getSdkPath ?? throw new ArgumentNullException (nameof (getSdkPath));
 }
 
+/// <summary>
+/// Gets the path to the emulator executable, or null if not found.
+/// </summary>
 public string? EmulatorPath {
 get {
 var sdkPath = getSdkPath ();
 if (string.IsNullOrEmpty (sdkPath))
 return null;
+
 var ext = OS.IsWindows ? ".exe" : "";
 var path = Path.Combine (sdkPath, "emulator", "emulator" + ext);
+
 return File.Exists (path) ? path : null;
 }
 }
 
-public bool IsAvailable => EmulatorPath != null;
+/// <summary>
+/// Gets whether the Android Emulator is available.
+/// </summary>
+public bool IsAvailable => EmulatorPath is not null;
 
 /// <summary>
 /// Starts an AVD and returns the process.
 /// </summary>
+/// <param name="avdName">The name of the AVD to start.</param>
+/// <param name="coldBoot">Whether to perform a cold boot (ignore snapshots).</param>
+/// <param name="additionalArgs">Additional command-line arguments.</param>
+/// <returns>The emulator process.</returns>
+/// <exception cref="InvalidOperationException">Thrown when Android Emulator is not found.</exception>
 public Process StartAvd (string avdName, bool coldBoot = false, string? additionalArgs = null)
 {
 if (!IsAvailable)
@@ -58,12 +76,16 @@ public Process StartAvd (string avdName, bool coldBoot = false, string? addition
 
 var process = new Process { StartInfo = psi };
 process.Start ();
+
 return process;
 }
 
 /// <summary>
 /// Lists the names of installed AVDs.
 /// </summary>
+/// <param name="cancellationToken">Cancellation token.</param>
+/// <returns>A list of AVD names.</returns>
+/// <exception cref="InvalidOperationException">Thrown when Android Emulator is not found.</exception>
 public async Task<List<string>> ListAvdNamesAsync (CancellationToken cancellationToken = default)
 {
 if (!IsAvailable)
@@ -77,14 +99,15 @@ public async Task<List<string>> ListAvdNamesAsync (CancellationToken cancellatio
 CreateNoWindow = true
 };
 
-var exitCode = await ProcessUtils.StartProcess (psi, stdout, null, cancellationToken).ConfigureAwait (false);
+await ProcessUtils.StartProcess (psi, stdout, null, cancellationToken).ConfigureAwait (false);
 
 var avds = new List<string> ();
 foreach (var line in stdout.ToString ().Split ('\n')) {
 var trimmed = line.Trim ();
 if (!string.IsNullOrEmpty (trimmed))
 avds.Add (trimmed);
 }
+
 return avds;
 }
 }