External Configuration Store Generator

[GenerateExternalConfigurationStore] creates a typed ExternalConfigurationStore<TSettings> factory from a static loader and ordered validators.

[GenerateExternalConfigurationStore(typeof(TenantFeatureSettings), FactoryName = "Create")]
public static partial class GeneratedTenantConfigStore
{
    [ExternalConfigurationLoader]
    private static ValueTask<ExternalConfigurationSnapshot<TenantFeatureSettings>> Load(CancellationToken ct) { }

    [ExternalConfigurationValidator("Tenant id is required.", 10)]
    private static bool HasTenant(TenantFeatureSettings settings) => !string.IsNullOrWhiteSpace(settings.TenantId);
}

The loader must return ValueTask<ExternalConfigurationSnapshot<TSettings>> and accept a CancellationToken. Validators must be static bool methods accepting TSettings.