Update Notes #2:

- Added dedicated Line pages for viewing a Line and its full thread. - Added comments to Lines so conversations can continue beyond the original post. - Added optional image attachments for comments. - Added comment counts to Lines in the feed. - Added optional Line titles for short, bold headers above Line content. - Added likes and dislikes for comments. - Added new notifications for comments and comment reactions. - Expanded mentions so dropping `@username` in a comment links to that user’s profile and sends a notification. - Updated notification links to open the relevant Line page directly. - Polished the comment interface with avatars, timestamps, reaction buttons, delete controls, and an empty-comments state.