Add ASP.NET Core controller registration docs and tests

[Copilot]

The existing AssignableTo + AsSelf capabilities already support registering controllers as DI services (equivalent to AddControllersAsServices()), but this wasn't documented or tested.

Tests

• AddAspNetCoreControllersAsServices — base case with AssignableTo = typeof(ControllerBase), AsSelf = true
• AddAspNetCoreControllersAsServicesWithTypeNameFilter — discovery via *Controller naming convention
• AddAspNetCoreControllersAsScopedServices — non-default lifetime
• AddAspNetCoreControllersWithExclusion — ExcludeByTypeName filtering

Documentation

New README section showing the three main patterns:

// Register all controllers inheriting from ControllerBase as transient services
[GenerateServiceRegistrations(
    AssignableTo = typeof(ControllerBase),
    AsSelf = true,
    Lifetime = ServiceLifetime.Transient)]
public static partial IServiceCollection AddControllersAsServices(this IServiceCollection services);

Also covers TypeNameFilter = "*Controller" and ExcludeByTypeName variants.

No generator code changes were needed — the existing feature set handles this use case.

[Copilot]

Pull request overview

Adds documentation and verifies via tests that the existing GenerateServiceRegistrations options (AssignableTo/TypeNameFilter + AsSelf) can be used to register ASP.NET Core controller types in the DI container, including lifetime and exclusion filtering.

Changes:

• Added four new generator tests covering controller discovery/registration scenarios (AssignableTo, TypeNameFilter, scoped lifetime, exclusions).
• Added a new README section documenting controller registration patterns with ServiceScan.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
ServiceScan.SourceGenerator.Tests/AddServicesTests.cs	Adds new tests that assert generated controller registrations for common MVC controller patterns.
README.md	Documents how to register controllers as DI services using existing generator options.

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[Copilot]

The README states this approach is equivalent to ASP.NET Core's IMvcBuilder.AddControllersAsServices(), but generating DI registrations alone does not switch MVC to resolve controllers from DI (it only adds the controller types to the container). To be equivalent, the docs should also instruct calling services.AddControllers().AddControllersAsServices() (or otherwise configuring ServiceBasedControllerActivator), and clarify what ServiceScan does vs what MVC needs.

[Copilot]

The usage snippet services.AddControllers(); services.AddControllersAsServices(); is misleading because the second call here is the generated IServiceCollection extension, not MVC's IMvcBuilder.AddControllersAsServices(). Consider updating the sample to call MVC's builder extension (e.g., services.AddControllers().AddControllersAsServices();) in addition to the generated registration method (and/or rename the generated method in the example to avoid confusion).

[Copilot]

Test name AddAspNetCoreControllersWithExclusion is inconsistent with the other controller tests (it omits AsServices). Renaming it to match the pattern would make the test suite easier to scan.

Suggested change

	public void AddAspNetCoreControllersWithExclusion()
	public void AddAspNetCoreControllersAsServicesWithExclusion()