Allow users to import Terraform state into Spacelift stacks via the CLI, in addition to the existing UI flow.

State import is only available through the Spacelift UI. Users must manually click through each stack one by one to import state files. For customers migrating large numbers of stacks, this is a significant manual bottleneck.

Desired behavior

A CLI command (e.g. spacectl stack state import) that accepts a state file path and a stack identifier, allowing state import to be scripted and automated as part of a migration pipeline.