start-issue

Start working on a Marshroom cart issue in the current repository.

Critical Requirements

• state.json update is MANDATORY. After creating the branch, you MUST update the issue status to running in ${MARSHROOM_STATE:-~/.config/marshroom/state.json}. If this fails, stop and report the error — do NOT silently continue.
• Use marsh start if available; otherwise fall back to direct jq atomic write (see step 10).

Steps