Comparison and getting boolean mask

I have an NDArray (say idmap1) and would like to compare it with a number to get a boolean mask (numpy boolean style), as shown below:

```
mask = ((idmap1 == 0) & (idmap2 != 1))
idmap1[mask] = idmap2[mask]
```

Is there a way to realize this using multik library? Thank you!

The issue names no files, tests, or code entry points. Start by locating Multik's NDArray comparison and indexing APIs, then determine how boolean masks would interact with element assignment. Done means the shown combined comparisons, mask-based selection, and assignment work as requested, with coverage for the behavior.

Written by the indexing model from the issue text.