feat(accounts): 账户列表显示实时并发数

- 在账户列表 API 返回中添加 current_concurrency 字段
- 合并平台和类型列为 PlatformTypeBadge 组件，节省表格空间
- 新增并发状态列，显示 当前/最大 并发数，支持颜色编码

backend/internal/service/concurrency_service.go

@@ -147,3 +147,20 @@ func CalculateMaxWait(userConcurrency int) int {
 	}
 	return userConcurrency + defaultExtraWaitSlots
 }
+
+// GetAccountConcurrencyBatch gets current concurrency counts for multiple accounts
+// Returns a map of accountID -> current concurrency count
+func (s *ConcurrencyService) GetAccountConcurrencyBatch(ctx context.Context, accountIDs []int64) (map[int64]int, error) {
+	result := make(map[int64]int)
+
+	for _, accountID := range accountIDs {
+		count, err := s.cache.GetAccountConcurrency(ctx, accountID)
+		if err != nil {
+			// If key doesn't exist in Redis, count is 0
+			count = 0
+		}
+		result[accountID] = count
+	}
+
+	return result, nil
+}