fix(instance-metadata): add required CreatedAt field

internal/entity/server_metadata.go

@@ -72,6 +72,7 @@ func NewInstanceMetadata(dbData *ent.InstanceMetadata) (*InstanceMetadata, error
 
 func (m InstanceMetadata) ToLysand() versia.InstanceMetadata {
 	return versia.InstanceMetadata{
+		CreatedAt:   versiautils.TimeFromStd(m.CreatedAt),
 		Extensions:  m.Extensions,
 		Name:        m.Name,
 		Description: m.Description,

internal/repository/repo_impls/instance_metadata_repository_impl.go

@@ -56,6 +56,7 @@ func (i *InstanceMetadataRepositoryImpl) ImportFromLysandByURI(ctx context.Conte
 	defer s.End()
 	ctx = s.Context()
 
+	// TODO: implement storing the instance metadata
 	//i.federationService.
 
 	return nil, nil

pkg/versia/instance_metadata.go

@@ -15,6 +15,9 @@ type InstanceMetadata struct {
 	// Type is always "InstanceMetadata"
 	Type string `json:"type"`
 
+	// CreatedAt is the initial date when the instance was first created
+	CreatedAt versiautils.Time `json:"created_at"`
+
 	// Extensions is a map of active extensions
 	Extensions Extensions `json:"extensions,omitempty"`