Expose header in history

commonspace/object/tree/objecttree/change.go

@@ -55,6 +55,7 @@ func NewChangeFromRoot(id string, ch *treechangeproto.RootChange, signature []by
 		IsSnapshot: true,
 		Identity:   string(ch.Identity),
 		Signature:  signature,
+		Data:       []byte(ch.ChangeType),
 	}
 }
 

commonspace/object/tree/objecttree/historytree.go

@@ -1,6 +1,9 @@
 package objecttree
 
-import "errors"
+import (
+	"errors"
+	"github.com/anytypeio/any-sync/commonspace/object/tree/treechangeproto"
+)
 
 var ErrLoadBeforeRoot = errors.New("can't load before root")
 
@@ -12,6 +15,8 @@ type HistoryTree interface {
 	Heads() []string
 	IterateFrom(id string, convert ChangeConvertFunc, iterate ChangeIterateFunc) error
 	GetChange(string) (*Change, error)
+	Header() *treechangeproto.RawTreeChangeWithId
+	UnmarshalledHeader() *Change
 }
 
 type historyTree struct {

commonspace/object/tree/objecttree/treefactory.go

@@ -187,5 +187,11 @@ func buildHistoryTree(deps objectTreeDeps, params HistoryTreeParams) (ht History
 	if err != nil {
 		return nil, err
 	}
+
+	header, err := objTree.changeBuilder.ConvertFromRaw(objTree.rawRoot, false)
+	if err != nil {
+		return nil, err
+	}
+	objTree.root = header
 	return hTree, nil
 }