Show comment sidebar for document owners, not just collaborators

Co-Authored-By: Claude Sonnet 4.6 <[e-mail]>

templates/document_edit.html

···
 {{end}}
 
 <!-- Comment sidebar -->
-{{if .IsCollaborator}}
+{{if or .IsCollaborator .IsOwner}}
 <div id="comment-sidebar" class="comment-sidebar">
     <div class="comment-sidebar-header">Comments</div>
     <div id="comment-threads" class="comment-threads"></div>