fix(rnotes): register comment and suggestion marks in legacy editor

The CommentMark, SuggestionInsertMark, and SuggestionDeleteMark extensions
were only registered in the collab (Yjs) editor, causing "no mark type
named 'comment'" crash when adding comments in demo/legacy mode.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

modules/rnotes/components/folk-notes-app.ts

@@ -1383,6 +1383,9 @@ Gear:          EUR  400 (10%)</code></pre><p><em>Maya is tracking expenses in rF
 				Image, TaskList, TaskItem.configure({ nested: true }),
 				Placeholder.configure({ placeholder: 'Start writing, or type / for commands...' }),
 				CodeBlockLowlight.configure({ lowlight }), Typography, Underline,
+				CommentMark,
+				SuggestionInsertMark,
+				SuggestionDeleteMark,
 			],
 			content,
 			onUpdate: ({ editor }) => {