feat(admin): 分组管理列表新增用量列与账号数分类

分组管理列表增强：

1. 今日/累计用量列：
   - 新增独立端点 GET /admin/groups/usage-summary
   - 一次查询返回所有分组的今日费用和累计费用（actual_cost）
   - 前端异步加载后合并显示在分组列表中

2. 账号数区分可用/限流/总量：
   - 将账号数列从单一总量改为 badge 内多行展示
   - 可用: active + schedulable 的账号数（绿色）
   - 限流: rate_limit/overload/temp_unschedulable 的账号数（橙色，无限流时隐藏）
   - 总量: 全部关联账号数

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/internal/repository/usage_log_repo.go

@@ -3000,6 +3000,7 @@ func (r *usageLogRepository) GetGroupStatsWithFilters(ctx context.Context, start
 	return results, nil
 }
 
+<<<<<<< HEAD
 // GetUserBreakdownStats returns per-user usage breakdown within a specific dimension.
 func (r *usageLogRepository) GetUserBreakdownStats(ctx context.Context, startTime, endTime time.Time, dim usagestats.UserBreakdownDimension, limit int) (results []usagestats.UserBreakdownItem, err error) {
 	query := `
@@ -3067,6 +3068,43 @@ func (r *usageLogRepository) GetUserBreakdownStats(ctx context.Context, startTim
 	return results, nil
 }
 
+// GetAllGroupUsageSummary returns today's and cumulative actual_cost for every group.
+// todayStart is the start-of-day in the caller's timezone (UTC-based).
+// TODO(perf): This query scans ALL usage_logs rows for total_cost aggregation.
+// When usage_logs exceeds ~1M rows, consider adding a short-lived cache (30s)
+// or a materialized view / pre-aggregation table for cumulative costs.
+func (r *usageLogRepository) GetAllGroupUsageSummary(ctx context.Context, todayStart time.Time) ([]usagestats.GroupUsageSummary, error) {
+	query := `
+		SELECT
+			g.id AS group_id,
+			COALESCE(SUM(ul.actual_cost), 0) AS total_cost,
+			COALESCE(SUM(CASE WHEN ul.created_at >= $1 THEN ul.actual_cost ELSE 0 END), 0) AS today_cost
+		FROM groups g
+		LEFT JOIN usage_logs ul ON ul.group_id = g.id
+		GROUP BY g.id
+	`
+
+	rows, err := r.sql.QueryContext(ctx, query, todayStart)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var results []usagestats.GroupUsageSummary
+	for rows.Next() {
+		var row usagestats.GroupUsageSummary
+		if err := rows.Scan(&row.GroupID, &row.TotalCost, &row.TodayCost); err != nil {
+>>>>>>> c8c1b4d4 (feat(admin): 分组管理列表新增用量列与账号数分类)
+			return nil, err
+		}
+		results = append(results, row)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return results, nil
+}
+
 // resolveEndpointColumn maps endpoint type to the corresponding DB column name.
 func resolveEndpointColumn(endpointType string) string {
 	switch endpointType {