feat: Replace avg votes per user with total evaluation time

models.py

@@ -701,8 +701,12 @@ def get_voting_statistics():
     # Total number of votes
     total_votes = Vote.query.count()
     
-    # Average votes per user
-    avg_votes_per_user = round(total_votes / total_voters, 1) if total_voters > 0 else 0
+    # Total evaluation time in seconds (sum of session durations)
+    total_eval_seconds = db.session.query(func.sum(Vote.session_duration_seconds)).scalar() or 0
+    
+    # Convert to hours, minutes format
+    total_eval_hours = int(total_eval_seconds // 3600)
+    total_eval_minutes = int((total_eval_seconds % 3600) // 60)
     
     # Total characters evaluated (sum of text lengths)
     total_characters = db.session.query(func.sum(func.length(Vote.text))).scalar() or 0
@@ -721,7 +725,8 @@ def get_voting_statistics():
     return {
         "total_voters": total_voters,
         "total_votes": total_votes,
-        "avg_votes_per_user": avg_votes_per_user,
+        "total_eval_hours": total_eval_hours,
+        "total_eval_minutes": total_eval_minutes,
         "total_characters": total_characters,
         "votes_last_24h": votes_last_24h,
         "votes_last_7d": votes_last_7d,

templates/leaderboard.html

@@ -1137,10 +1137,10 @@
             </div>
             
             <div class="stat-card accent">
-                <div class="stat-icon">📈</div>
+                <div class="stat-icon">⏱️</div>
                 <div class="stat-content">
-                    <div class="stat-value">{{ voting_stats.avg_votes_per_user }}</div>
-                    <div class="stat-label">인당 평균 투표</div>
+                    <div class="stat-value">{% if voting_stats.total_eval_hours > 0 %}{{ voting_stats.total_eval_hours }}시간 {% endif %}{{ voting_stats.total_eval_minutes }}분</div>
+                    <div class="stat-label">총 평가 시간</div>
                 </div>
             </div>