st

Manage persistent task plans in repo-committed JSONL (`.step/st-plan.jsonl`) so state survives turns/sessions and stays reviewable in git. Use when users ask to "use $st", "resume the plan", "export/import plan state", "checkpoint milestones", "track dependencies/blocked work", "show ready next tasks", "keep shared TODO status on disk", "map a `$select` plan into durable execution state", "prove `$st` works for implementation tracking", or diagnose/repair `st-plan.jsonl` concerns (for example append-only vs mutable semantics, lock-file gitignore policy, or seq/checkpoint integrity).