feat: Add CSV upload support in Team Leaderboard

📌 Changes

• Converted team upload from JSON to CSV format
• Added support for college_name field
• Implemented CSV parsing and grouping of team members
• Updated UI to reflect CSV upload
• Removed unnecessary .codex file

📄 CSV Format

team_name,project_name,college_name,member_name,username

✅ Testing

• CSV upload tested successfully
• Teams displayed correctly
• Members grouped properly

Screenshots or screen recordings

Before	After

🎯 Result

CSV-based team upload is working as expected.

###Realted issues

#67