Propagate exit codes from RunAsync in Akade, ImageSharp, bepuphysics2

Capture the summaries returned by BenchmarkSwitcher.RunAsync and return
summaries.ToExitCode() so CI can detect benchmark failures and critical
validation errors via a non-zero process exit code.

Addresses Copilot review comments on PR #5227.

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

Author: DrewScoggins

src/benchmarks/real-world/Akade.IndexedSet.Benchmarks/Program.cs

@@ -5,7 +5,8 @@
 
 // Use RunAsync (not Run) so BDN does not install its single-threaded
 // BenchmarkDotNetSynchronizationContext on the entrypoint thread.
-await BenchmarkSwitcher.FromAssembly(typeof(Program).Assembly).RunAsync(args, RecommendedConfig.Create(
+var summaries = await BenchmarkSwitcher.FromAssembly(typeof(Program).Assembly).RunAsync(args, RecommendedConfig.Create(
                     artifactsPath: new DirectoryInfo(Path.Combine(Path.GetDirectoryName(typeof(Program).Assembly.Location)!, "BenchmarkDotNet.Artifacts")),
                     mandatoryCategories: ImmutableHashSet.Create(Categories.AkadeIndexedSet)))
-    .ConfigureAwait(false);
+    .ConfigureAwait(false);
+return summaries.ToExitCode();

src/benchmarks/real-world/ImageSharp/Program.cs

@@ -19,14 +19,15 @@ public class Program
         /// </param>
         // Use RunAsync (not Run) so BDN does not install its single-threaded
         // BenchmarkDotNetSynchronizationContext on the entrypoint thread.
-        public static async Task Main(string[] args)
+        public static async Task<int> Main(string[] args)
         {
-            await BenchmarkSwitcher
+            var summaries = await BenchmarkSwitcher
                 .FromAssembly(typeof(Program).Assembly)
                 .RunAsync(args, RecommendedConfig.Create(
                         artifactsPath: new DirectoryInfo(Path.Combine(Path.GetDirectoryName(typeof(Program).Assembly.Location), "BenchmarkDotNet.Artifacts")),
                         mandatoryCategories: ImmutableHashSet.Create(Categories.ImageSharp)))
                 .ConfigureAwait(false);
+            return summaries.ToExitCode();
         }
     }
 }

src/benchmarks/real-world/bepuphysics2/Program.cs

@@ -9,13 +9,14 @@ public class BepuPhysics2Benchmarks
 {
     // Use RunAsync (not Run) so BDN does not install its single-threaded
     // BenchmarkDotNetSynchronizationContext on the entrypoint thread.
-    public static async Task Main(string[] args)
+    public static async Task<int> Main(string[] args)
     {
-        await BenchmarkSwitcher
+        var summaries = await BenchmarkSwitcher
             .FromAssembly(typeof(BepuPhysics2Benchmarks).Assembly)
             .RunAsync(args, RecommendedConfig.Create(
                     artifactsPath: new DirectoryInfo(Path.Combine(Path.GetDirectoryName(typeof(BepuPhysics2Benchmarks).Assembly.Location), "BenchmarkDotNet.Artifacts")),
                     mandatoryCategories: ImmutableHashSet.Create(Categories.BepuPhysics)))
             .ConfigureAwait(false);
+        return summaries.ToExitCode();
     }
 }