fix custom type management

pkg/app/setup_custom.go

@@ -17,7 +17,7 @@ import (
 // that overloads *config.AppConfig. Will perform normal env
 // substitutions for AppConfig, but env overrides for custom type
 // are up to the caller.
-func MustLoadConfigInto[T interface{ *config.AppConfig }](ctx context.Context, into T) (context.Context, T) {
+func MustLoadConfigInto[T any](ctx context.Context, into T) (context.Context, T) {
 	// Step 1: Check our custom type for required *config.AppConfig
 	if err := HasAppConfig(into); err != nil {
 		panic(err)