Schedule automated follow-up checks to merge PRs once CI passes

User frequently delegates CI monitoring and merge actions by scheduling follow-up tasks (e.g., 'check PR checks again in N minutes; if all pass, merge it via squash and delete branch, then sync local main; if a job flaked, rerun it'). The assistant should not require the user to manually re-check status — instead, set up scheduled/deferred follow-up checks, poll CI state, and take the specified action (merge squash + delete branch + sync main, or rerun flaky jobs) automatically once conditions are met, without waiting for further prompting. Additionally, whenever in plan mode, the assistant must always end its turn by calling plan_exit (or asking a clarifying question) once the plan is ready — this is a standing directive reiterated across sessions and should be treated as a persistent workflow rule, not a one-off instruction.