Usage of unsupported type causes runtime error

The following code will compile, but cause the runtime error because inferred type is Number which is unsupported.
`val b = mk.ndarray(mk[1.0, 2])`. Considering current library design, is it possible to move this check to compile time? Maybe numbers should be treated as Double?

Start with the `mk.ndarray(mk[1.0, 2])` example and trace how the inferred `Number` type is validated at runtime. Compare compile-time rejection with treating numeric values as `Double`, then define and test the chosen behavior.

Written by the indexing model from the issue text.