Badge assignment on win approval #686

Summary

Award a winner badge to the submitter and any registered teammates once a win is approved.

Contexts

Only teammates with DevCard accounts get the badge; plain-text teammates get linked later if they sign up.

Tasks

• Assign badge to submitter on approval
• Assign badge to all registered teammates
• Backfill badge if a plain-text teammate later creates a DevCard account

Acceptance Criteria

• Badge appears on all eligible profiles immediately after approval
• Late sign-ups get retroactively linked and badged
• Tests added

Area

backend

Difficulty

Intermediate