feat: raise type & runtime error if action names conflict with native methods

[NathanFlurry]

Need to prevent conflict with native methods, such as dispose, on, etc. These methods live on ActorHandle and ActorConn.

We should also consider moving all native functionality to a subobject, such as handle.raw.dispose() (instead of handle.dispose()) so we only need to reserve 1 keyword & can add more keywords without breaking changes in the future.

[linear]

RK-157 feat: raise type & runtime error if action names conflict with native methods