Factory async + pooling: generator DI/Autofac integration

[Skymly]

Problem

Phase 2 (PR #189) added async/pooled registry generation but without DI/Autofac integration. The generated {Contract}AsyncRegistry and {Contract}PooledRegistry classes only emit Create() (DirectNew). They need Create(IServiceProvider), Create(ILifetimeScope), RegisterDi, and RegisterAutofac methods when DI/Autofac integration is enabled.

Changes

Refactor

• Extract CreateAsyncFactoryRegistryBuilderExpression and CreatePooledFactoryRegistryBuilderExpression from FactorySyntaxFactory into shared helpers that accept RegistrationResolveTarget (DirectNew/ServiceProvider/ComponentContext)

DiIntegrationSyntaxHelper (new methods)

• CreateAsyncFactoryCreateFromServiceProviderMethod — generates Create(IServiceProvider) for async registry
• CreatePooledFactoryCreateFromServiceProviderMethod — generates Create(IServiceProvider) for pooled registry
• CreateAsyncFactoryRegistryBuilderExpression(contract, entries, resolveTarget) — builder chain with ServiceProvider resolution
• CreatePooledFactoryRegistryBuilderExpression(contract, entries, poolSize, resolveTarget) — builder chain with WithPooling + ServiceProvider resolution
• CreateAsyncFactoryRegistryInterfaceType / CreatePooledFactoryRegistryInterfaceType — type syntax helpers

AutofacIntegrationSyntaxHelper (new methods)

• CreateAsyncFactoryCreateFromComponentContextMethod — generates Create(ILifetimeScope) for async registry
• CreatePooledFactoryCreateFromComponentContextMethod — generates Create(ILifetimeScope) for pooled registry

FactorySyntaxFactory

• CreateAsyncRegistryCompilationUnit: add DI members when EnableDi, Autofac members when EnableAutofac
• CreatePooledRegistryCompilationUnit: same

Generated code structure

• Create(IServiceProvider): uses serviceProvider.GetRequiredService() with async lambda ct => ...CreateAsync(ct) or sync () => ...
• Create(ILifetimeScope): uses lifetimeScope.Resolve() with same lambda logic
• RegisterDi: registers impl types as Transient, registry as Singleton via TryAdd
• RegisterAutofac: registers impl types with InstanceSharing, registry as SingleInstance lambda

Tests (4 Verify snapshots)

• EmitsRegisterDiWhenDiIntegrationEnabledForAsyncFactory
• EmitsRegisterDiWhenDiIntegrationEnabledForPooledFactory
• EmitsRegisterAutofacWhenAutofacIntegrationEnabledForAsyncFactory
• EmitsRegisterAutofacWhenAutofacIntegrationEnabledForPooledFactory

Module

SourceGenerators