Dev sprints: phased, resumable builds behind all-green test gates. Use whenever the user wants to build or extend a feature via "dev sprints," "phased plan," "gatelog," or an autonomous/cron-driven multi-session build; to resume an in-progress phased build (existing plan.md + gatelog.md in a project dir); or to kick one off from a natural-language idea, a spec/ticket, or a target project folder. Always check for an existing gatelog.md before planning from scratch — this skill is idempotent and must resume rather than replan when one is found.
