`Environment` constructors should check input and return `Result`

[lionel-]

Environment methods are doing dangerous things with inner (e.g. defineVar()) which hasn't been sufficiently type-checked.

E.g. here we are not checking that input is an environment:

ark/crates/harp/src/environment.rs

Line 55 in aba06d0

pub fn new(env: RObject) -> Self {