Spec Kit Extension

Native extension (spec-kit/extension, id ackit) with 7 commands, each delegating to ackit-speckit:

specify extension add ackit --dev ./spec-kit/extension
specify extension list
specify artifact list --json

Commands: speckit.ackit.sync|status|verify|gate|checkpoint|handoff|complete. Hooks: after_specify, after_plan, after_tasks → sync; before_implement → status preflight; after_implement → verify (never auto-completes). Workflow package spec-kit/workflow/workflow.yml (ackit-verified-sdd) encodes the verified SDD cycle.