feat: Update profile following logic and UI enhancements
- Adjusted the profile following logic to correctly update followers count on follow/unfollow actions.
- Refactored CommentsPage to use Riverpod for state management, improving loading and error handling.
- Introduced CommentInputSheet for better comment submission UX.
- Enhanced CreateGalleryPage UI with improved layout and button styles.
- Updated GalleryPage to support pull-to-refresh functionality and improved layout.
- Modified ProfilePage to use a smaller button size for follow/unfollow actions.
- Added AppButtonSize enum to manage button sizes consistently across the app.
- Improved PlainTextField styling for better focus indication and usability.