Enhanced public writer profile (stats, badges) #120

Strengthen the public writer profile page to make it feel like an achievement worth building. Writers should feel they're building a professional presence.

Context: A compelling profile is a long-term reason for writers to stay on the platform rather than moving to personal blogs.

Improvements:

• Total article views count
• Total reactions received
• Joined date and streak
• Badge system (e.g. '10 articles', 'First series', 'Top contributor')
• RSS feed link per profile (/[username]/rss.xml)