advance

Move a contract forward by exactly one step. Asks the script what the next move is, then takes it: start the sub-tasks that are ready, escalate a failure to the architect, land a finished contract that has a parent branch (a background script, no question asked) or hand one without a parent branch to verification, or report what is blocked and why. Makes one move and stops, because a merge-gated loop suspends until somebody merges and /pr-merged wakes it. Use when: user says /advance, 'what is next on this contract', 'start the next sub-task', 'continue the contract', or after /pr-merged reports newly released sub-tasks. Never iterates on its own.