[TODO Import][Server][Backlog] Activity heatmap data tracking

[ferneediaz]

Imported from server/TODO.md.

Kanban

• Column: Backlog
• Area: Server

📋 TODO - Activity Heatmap Data (LOW PRIORITY)

Track daily activity for GitHub-style heatmap on profiles.

Task Breakdown:

1. Prisma Schema Updates

• Add DailyActivity model (id, userId, date, gamesPlayed, gamesWon, createdAt)
• Unique constraint on [userId, date]
• Run migration
• Success Criteria: Schema compiles ✅

2. Implementation

• Increment gamesPlayed / gamesWon after each battle completion
• GET /api/users/:id/activity?year=2026 — Get 365 days of activity data
• Success Criteria: Heatmap data returns correctly ✅

3. Tests

• Activity tracking tests
• Year boundary tests
• Success Criteria: All activity tests passing ✅

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