UPGRADE PATCH - Innings + Chase Overlay + Team Assignment Fix

Added:
1. Dashboard End Innings button
   - File: partials/scoreboard_panel.php
   - Function: endCurrentInnings() in assets/js/scoring.js
   - API: api/end_innings.php

2. First innings complete flow
   - Manual End Innings marks innings_completed=1
   - Sets first_innings_runs
   - Sets target = first innings runs + 1
   - Shows Next Innings player selector box

3. Second innings chase overlay
   - overlay.php now includes RRR field
   - assets/js/overlay.js shows:
     CRR / RRR / TARGET / NEED runs from balls
   - This appears when target > 0

4. Team assignment fixed
   - api/team_assign_crud.php now removes old team assignment before assigning a player to a new team
   - One player will not show under two teams anymore
   - api/players_crud.php now returns assigned_team details
   - manager.js shows assigned team on player card and preselects current team when editing

Important:
- Existing overlay design was kept.
- Existing DB table structure was not changed.