feat!: modernize host setup API with ASP.NET Core minimal API pattern

BREAKING CHANGE: Replace PipelineHostBuilder with new PipelineBuilder API

This is a complete redesign of the pipeline configuration API to follow
ASP.NET Core's WebApplicationBuilder pattern:

Before (callback-based):
  await PipelineHostBuilder.Create()
      .ConfigureServices((context, services) => { services.AddModule<MyModule>(); })
      .ConfigurePipelineOptions((context, options) => { })
      .ExecutePipelineAsync();

After (direct property access):
  var builder = Pipeline.CreateBuilder();
  builder.Services.AddModule<MyModule>();
  builder.Options.DefaultRetryCount = 3;
  await builder.Build().RunAsync();

Changes:
- New Pipeline.CreateBuilder() static factory method
- New PipelineBuilder with direct property access (Services, Configuration, Options)
- New IPipeline interface for built pipelines (replaces IPipelineHost)
- New PipelineBuilderExtensions for convenience methods (AddModule, ConfigureServices)
- Remove PipelineHostBuilder, PipelineHost, IPipelineHost
- Remove callback-based configuration methods
- Update all examples and tests to use new API

Closes #2065

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: thomhurst

src/ModularPipelines.Build/Program.cs

@@ -9,88 +9,85 @@
 using ModularPipelines.Build.Modules.LocalMachine;
 using ModularPipelines.Build.Settings;
 using ModularPipelines.Extensions;
-using ModularPipelines.Host;
 using Octokit;
 using Octokit.Internal;
 
-await PipelineHostBuilder.Create()
-    .ConfigureAppConfiguration((_, builder) =>
-    {
-        builder.AddJsonFile("appsettings.json")
-            .AddUserSecrets<Program>()
-            .AddEnvironmentVariables();
-    })
-    .ConfigureServices((context, collection) =>
-    {
-        collection.Configure<PipelineSettings>(context.Configuration.GetSection("Pipeline"));
-        collection.Configure<NuGetSettings>(context.Configuration.GetSection("NuGet"));
-        collection.Configure<LocalNuGetSettings>(context.Configuration.GetSection("LocalNuGet"));
-        collection.Configure<GitHubSettings>(context.Configuration.GetSection("GitHub"));
-        collection.Configure<PublishSettings>(context.Configuration.GetSection("Publish"));
-        collection.Configure<CodacySettings>(context.Configuration.GetSection("Codacy"));
-        collection.Configure<CodeCovSettings>(context.Configuration.GetSection("CodeCov"));
-
-        collection
-            .AddModule<RunUnitTestsModule>()
-            .AddModule<NugetVersionGeneratorModule>()
-            .AddModule<FindProjectsModule>()
-            .AddModule<FindProjectDependenciesModule>()
-            .AddModule<PackProjectsModule>()
-            .AddModule<PackageFilesRemovalModule>()
-            .AddModule<PackagePathsParserModule>()
-            .AddModule<CodeFormattedNicelyModule>()
-            .AddModule<GenerateReadMeModule>()
-            .AddModule<FormatMarkdownModule>()
-            .AddModule<ChangedFilesInPullRequestModule>()
-            .AddModule<DependabotCommitsModule>()
-            .AddModule<PrintEnvironmentVariablesModule>()
-            .AddModule<PrintGitInformationModule>()
-            .AddModule<PushVersionTagModule>()
-            .AddPipelineModuleHooks<MyModuleHooks>();
+var builder = Pipeline.CreateBuilder(args);
 
-        collection.AddSingleton<IGitHubClient>(sp =>
-        {
-            var githubSettings = sp.GetRequiredService<IOptions<GitHubSettings>>();
-            var pipelineSettings = sp.GetRequiredService<IOptions<PipelineSettings>>();
+builder.Configuration
+    .AddJsonFile("appsettings.json")
+    .AddUserSecrets<Program>()
+    .AddEnvironmentVariables();
 
-            var githubToken = githubSettings.Value.StandardToken;
+builder.Services.Configure<PipelineSettings>(builder.Configuration.GetSection("Pipeline"));
+builder.Services.Configure<NuGetSettings>(builder.Configuration.GetSection("NuGet"));
+builder.Services.Configure<LocalNuGetSettings>(builder.Configuration.GetSection("LocalNuGet"));
+builder.Services.Configure<GitHubSettings>(builder.Configuration.GetSection("GitHub"));
+builder.Services.Configure<PublishSettings>(builder.Configuration.GetSection("Publish"));
+builder.Services.Configure<CodacySettings>(builder.Configuration.GetSection("Codacy"));
+builder.Services.Configure<CodeCovSettings>(builder.Configuration.GetSection("CodeCov"));
 
-            if (string.IsNullOrEmpty(githubToken))
-            {
-                githubToken = "token";
-            }
+builder.Services
+    .AddModule<RunUnitTestsModule>()
+    .AddModule<NugetVersionGeneratorModule>()
+    .AddModule<FindProjectsModule>()
+    .AddModule<FindProjectDependenciesModule>()
+    .AddModule<PackProjectsModule>()
+    .AddModule<PackageFilesRemovalModule>()
+    .AddModule<PackagePathsParserModule>()
+    .AddModule<CodeFormattedNicelyModule>()
+    .AddModule<GenerateReadMeModule>()
+    .AddModule<FormatMarkdownModule>()
+    .AddModule<ChangedFilesInPullRequestModule>()
+    .AddModule<DependabotCommitsModule>()
+    .AddModule<PrintEnvironmentVariablesModule>()
+    .AddModule<PrintGitInformationModule>()
+    .AddModule<PushVersionTagModule>()
+    .AddPipelineModuleHooks<MyModuleHooks>();
 
-            return new GitHubClient(new ProductHeaderValue(pipelineSettings.Value.GitHubProductHeader),
-                new InMemoryCredentialStore(new Credentials(githubToken)));
-        });
+builder.Services.AddSingleton<IGitHubClient>(sp =>
+{
+    var githubSettings = sp.GetRequiredService<IOptions<GitHubSettings>>();
+    var pipelineSettings = sp.GetRequiredService<IOptions<PipelineSettings>>();
 
-        // Local NuGet modules should only run in local development, not CI
-        // IsDevelopment() returns true for both local dev AND PR builds in CI (DOTNET_ENVIRONMENT=Development)
-        // Check common CI environment variables to distinguish local dev from CI
-        var isRunningInCI = !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("CI"))
-            || !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("GITHUB_ACTIONS"))
-            || !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("TF_BUILD"))
-            || !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("GITLAB_CI"));
-        var isLocalDevelopment = context.HostingEnvironment.IsDevelopment() && !isRunningInCI;
+    var githubToken = githubSettings.Value.StandardToken;
 
-        if (isLocalDevelopment)
-        {
-            collection.AddModule<CreateLocalNugetFolderModule>()
-                .AddModule<AddLocalNugetSourceModule>()
-                .AddModule<UploadPackagesToLocalNuGetModule>();
-        }
-        else if (!context.HostingEnvironment.IsDevelopment())
-        {
-            // Production environment (main branch CI)
-            collection.AddModule<UploadPackagesToNugetModule>()
-                .AddModule<CreateReleaseModule>();
-        }
-        // else: CI Development mode (PR builds) - don't register local NuGet or production upload modules
-    })
-    .ConfigurePipelineOptions((context, options) =>
+    if (string.IsNullOrEmpty(githubToken))
     {
-        var pipelineSettings = context.Configuration.GetSection("Pipeline").Get<PipelineSettings>() ?? new PipelineSettings();
-        options.DefaultRetryCount = pipelineSettings.DefaultRetryCount;
-    })
-    .SetLogLevel(LogLevel.Debug) // Temporarily hardcoded for debugging
-    .ExecutePipelineAsync();
+        githubToken = "token";
+    }
+
+    return new GitHubClient(new ProductHeaderValue(pipelineSettings.Value.GitHubProductHeader),
+        new InMemoryCredentialStore(new Credentials(githubToken)));
+});
+
+// Local NuGet modules should only run in local development, not CI
+// IsDevelopment() returns true for both local dev AND PR builds in CI (DOTNET_ENVIRONMENT=Development)
+// Check common CI environment variables to distinguish local dev from CI
+var isRunningInCI = !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("CI"))
+    || !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("GITHUB_ACTIONS"))
+    || !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("TF_BUILD"))
+    || !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("GITLAB_CI"));
+var isLocalDevelopment = builder.Environment.IsDevelopment() && !isRunningInCI;
+
+if (isLocalDevelopment)
+{
+    builder.Services.AddModule<CreateLocalNugetFolderModule>()
+        .AddModule<AddLocalNugetSourceModule>()
+        .AddModule<UploadPackagesToLocalNuGetModule>();
+}
+else if (!builder.Environment.IsDevelopment())
+{
+    // Production environment (main branch CI)
+    builder.Services.AddModule<UploadPackagesToNugetModule>()
+        .AddModule<CreateReleaseModule>();
+}
+// else: CI Development mode (PR builds) - don't register local NuGet or production upload modules
+
+var pipelineSettings = builder.Configuration.GetSection("Pipeline").Get<PipelineSettings>() ?? new PipelineSettings();
+builder.Options.DefaultRetryCount = pipelineSettings.DefaultRetryCount;
+
+builder.SetLogLevel(LogLevel.Debug); // Temporarily hardcoded for debugging
+
+var pipeline = builder.Build();
+await pipeline.RunAsync();