v7.0.6

What's Changed in v7.0.6

• Fixed duplicate entries in Global Stats leaderboard with intelligent client-side deduplication.
• Fixed playback history & listening hours reset after logout/login.
• Ensured playlist songs map deduplication on restore.
• Upgraded schema and added duplicate cleanup scripts in supabase_schema.sql.
• Bumped version to 7.0.6 (versionCode 175).