feat: add C ndarray interface and refactor implementation for stats/base/dmeanlipw
          
            #11817
        
      | Job | Run time | 
|---|---|
| 3s | |
| 3s | 
stats/base/dmeanlipw
          
            #11817
        
| Job | Run time | 
|---|---|
| 3s | |
| 3s |