- Split admin users page into player/tier-1/tier-2 tabs with affiliation labels and context-specific create dialogs
- Add media library with uploaded_files migration, list/delete unused files API, and admin nav route
- Enforce player username format (alphanumeric 3-32) on frontend and backend via shared package
- Improve admin dialog/panel styling; refine player parlay and match bet card kickoff display
Co-authored-by: Cursor <cursoragent@cursor.com>
