- Controller detects logged-in coach's disciplines via employee_id → sa_coaches
- Pending players filtered to those whose selected_disciplines overlap with
  coach's disciplines (or manual dropdown filter)
- Available groups in assess form filtered by player's selected disciplines
  intersected with coach's disciplines
- Added discipline filter dropdown to assessment index page
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>