Schedule delayed action checks

Schedule delayed one-shot or bounded polling with minimal heartbeats

Waiting for external state (CI pipeline, PR status, scheduled check) with bounded polling and clean output.

• · One-shot: --minutes N | --until HH:MM|ISO [--action 'text']
• · Polling: --every Nm|Xs --for Nm|Xs|--attempts N [--action 'text']
• · Stop-on-success: add --stop-on-success --prompt <name> | --prompt-text '...'

• · Heartbeat per minute (or interval) showing liveness
• · Action text printed on completion

• · Task tool (delegating to delay-once or delay-poll agents)
• · delay-run.sh script (for sleep, polling, success checks)

• · Max duration or attempts set for polling (no unbounded loops)
• · Success-check prompt returns JSON with {Success, Cancelled, Message}
• · Minimum polling interval enforced (e.g., ≥1m)

• · Unbounded poll requested → rejected with error
• · Success-check prompt malformed → polling stops with parse error
• · Polling duration exceeded → stops cleanly with timeout message
• · Network unavailable during stop-on-success check → retries on next interval

• · Minimal heartbeat spam (once/minute or per interval)
• · Graceful timeout handling (no runaway loops)
• · Stop-on-success avoids polling after condition met
• · Action text provides context for post-delay follow-up