Add minimal ExampleRunner example

- Created new ExampleRunner example that discovers and runs all examples sequentially
- Minimal implementation with no UI - just console output
- Discovers examples from Examples directory and runs them with FakeDriver
- Shows success/failure status for each example
- Returns exit code 0 if all pass, 1 if any fail

Note: Key injection via ExampleContextInjector needs debugging for out-of-process mode

Co-authored-by: tig <585482+tig@users.noreply.github.com>

Examples/ExampleRunner/Program.cs

@@ -0,0 +1,103 @@
+#nullable enable
+// Example Runner - Demonstrates discovering and running all examples using the example infrastructure
+
+using System.Diagnostics.CodeAnalysis;
+using Terminal.Gui.Examples;
+
+[assembly: ExampleMetadata ("Example Runner", "Discovers and runs all examples sequentially")]
+[assembly: ExampleCategory ("Infrastructure")]
+
+// Discover examples from the Examples directory
+string? assemblyDir = Path.GetDirectoryName (System.Reflection.Assembly.GetExecutingAssembly ().Location);
+
+if (assemblyDir is null)
+{
+    Console.WriteLine ("Error: Could not determine assembly directory");
+
+    return 1;
+}
+
+// Go up to find the Examples directory - from bin/Debug/net8.0 to Examples
+string examplesDir = Path.GetFullPath (Path.Combine (assemblyDir, "..", "..", "..", ".."));
+
+if (!Directory.Exists (examplesDir))
+{
+    Console.WriteLine ($"Error: Examples directory not found: {examplesDir}");
+
+    return 1;
+}
+
+Console.WriteLine ($"Searching for examples in: {examplesDir}\n");
+
+// Discover all examples - look specifically in each example's bin directory
+List<ExampleInfo> examples = [];
+HashSet<string> seen = [];
+
+foreach (string dir in Directory.GetDirectories (examplesDir))
+{
+    string binDir = Path.Combine (dir, "bin", "Debug", "net8.0");
+
+    if (!Directory.Exists (binDir))
+    {
+        continue;
+    }
+
+    foreach (ExampleInfo example in ExampleDiscovery.DiscoverFromDirectory (binDir, "*.dll", SearchOption.TopDirectoryOnly))
+    {
+        // Don't include this runner in the list and avoid duplicates
+        if (example.Name != "Example Runner" && seen.Add (example.Name))
+        {
+            examples.Add (example);
+        }
+    }
+}
+
+Console.WriteLine ($"Discovered {examples.Count} examples\n");
+
+// Run all examples sequentially
+var successCount = 0;
+var failCount = 0;
+
+foreach (ExampleInfo example in examples)
+{
+    Console.Write ($"Running: {example.Name,-40} ");
+
+    // Create context for running the example
+    ExampleContext context = new ()
+    {
+        DriverName = "FakeDriver",
+        KeysToInject = ["Esc"], // Just press Esc to quit each example
+        TimeoutMs = 5000,
+        Mode = ExecutionMode.OutOfProcess
+    };
+
+    try
+    {
+        ExampleResult result = ExampleRunner.Run (example, context);
+
+        if (result.Success)
+        {
+            Console.WriteLine ($"✓ Success");
+            successCount++;
+        }
+        else if (result.TimedOut)
+        {
+            Console.WriteLine ($"✗ Timeout");
+            failCount++;
+        }
+        else
+        {
+            Console.WriteLine ($"✗ Failed: {result.ErrorMessage ?? "Unknown"}");
+            failCount++;
+        }
+    }
+    catch (Exception ex)
+    {
+        Console.WriteLine ($"✗ Exception: {ex.Message}");
+        failCount++;
+    }
+}
+
+Console.WriteLine ($"\n=== Summary: {successCount} passed, {failCount} failed ===");
+
+return failCount == 0 ? 0 : 1;