handle nil properly with file nodes

pkg/gui/filetree/commit_file_node.go

@@ -17,5 +17,9 @@ func NewCommitFileNode(node *Node[models.CommitFile]) *CommitFileNode {
 
 // returns the underlying node, without any commit-file-specific methods attached
 func (self *CommitFileNode) Raw() *Node[models.CommitFile] {
+	if self == nil {
+		return nil
+	}
+
 	return self.Node
 }

pkg/gui/filetree/file_node.go

@@ -19,6 +19,10 @@ func NewFileNode(node *Node[models.File]) *FileNode {
 
 // returns the underlying node, without any file-specific methods attached
 func (self *FileNode) Raw() *Node[models.File] {
+	if self == nil {
+		return nil
+	}
+
 	return self.Node
 }