tkt-orient

Start-of-session pickup from the reconciled plan and tickets: read the frontier, in-progress threads, and plan ordering that tkt-reconcile left behind, flag stale WIP, and propose the next step. Use when starting a session, resuming after a break, or asking 'where were we?' / 'what's next?' / 'pick up where we left off'. Trigger: start of session, orient, resume, pick up where we left off, where were we, what's next, catch me up, continue, session start, what's on the board.