[Copilot]

Adds a 5th summary tile — Quizzes Taken (last 7 days) — to the dashboard, placed in the center of the tile row. All tiles are resized and fonts reduced to accommodate the new layout. For admin users, the count reflects activity across all students.

Backend (api/quiz.go)

• Computes quizzes_last_7_days in GetProgressHandler by filtering quizAttempts where StartTime is within the past 7 days (inclusive boundary via !Before())
• Adds the field to the /progress JSON response

sevenDaysAgo := time.Now().AddDate(0, 0, -7)
for _, qa := range quizAttempts {
    if !qa.StartTime.Before(sevenDaysAgo) {
        quizzesLast7Days++
    }
}

Frontend (dashboard.html, dashboard.js)

• Tile row changed from col-md-3 × 4 to col equal-width layout (row-cols-2 row-cols-md-5) to fit 5 tiles
• Card title font reduced h5 → h6; data font reduced h2 → h3; padding tightened to p-2
• New bg-secondary tile inserted at position 3 (middle); dashboard.js binds it to quizzes_last_7_days

Tests (api/handlers_test.go)

• TestGetProgressHandlerQuizzesLast7Days: creates attempts at −3d, −6d, and −10d; asserts quizzes_last_7_days == 2 while total_quizzes == 3