execute

Executor for plans approved by /ac:plan. Runs entirely on the main thread (Opus 4.8) with an auto-continue policy: wave-by-wave loop until the plan is complete, no schedule/wakeup polling. Spawns tier-routed worker subagents (ac:plan-worker-quick → haiku, ac:plan-worker-junior → sonnet, ac:plan-worker-senior → opus). Per-step 4-layer verification (Automated + Manual Code Review + Hands-on QA + Plan state) by the main thread. Wave-after checkpoint commits for complex plans. Final code-review by ac:plan-code-review (standard 4-stage) or ac:plan-code-deep-review (complex 6-stage) plus ac:oracle in parallel (complex only, --no-oracle opt-out). TDD enforcement when the plan's Conventions say so. Targets 0-iter quality with max-5 + stall revision loop.