Chore: Add AwaitHealthy to ModuleEngine and Server (#72215)

* Chore: Add AwaitHealthy to ModuleEngine and Server

* switch from fmt.Errorf to errors.New

Co-authored-by: Will Browne <wbrowne@users.noreply.github.com>

---------

Co-authored-by: Will Browne <wbrowne@users.noreply.github.com>

pkg/modules/modules.go

@@ -15,6 +15,7 @@ import (
 )
 
 type Engine interface {
+	AwaitHealthy(context.Context) error
 	Init(context.Context) error
 	Run(context.Context) error
 	Shutdown(context.Context) error
@@ -59,6 +60,14 @@ func ProvideService(
 	}
 }
 
+// AwaitHealthy waits for all registered modules to be healthy.
+func (m *service) AwaitHealthy(ctx context.Context) error {
+	if m.serviceManager == nil {
+		return errors.New("service manager has not been initialized")
+	}
+	return m.serviceManager.AwaitHealthy(ctx)
+}
+
 // Init initializes all registered modules.
 func (m *service) Init(_ context.Context) error {
 	var err error