implement

# Implement Execute an implementation plan created by `/create-plan`. Read the plan thoroughly, execute each step in order, emit a structured trajectory for every phase boundary, and report on the completed work. **Version history (v1.3-v1.7):** the emission discipline evolved through several versions — v1.6 typed flags (one `Bash` call per event, no temp file), v1.7 the emit-time sequencing guard (exit `5`) and the run-level `--verify` files reconciliation. The current, authoritative invariants are the **Trajectory emission contract** immediately below (and restated in Phase 2, Phase 5, and the NEVER list); the full per-version changelog lives in `references/implement-details.md`. ## Trajectory emission contract The trajectory (`outputs/operations/implement/_trajectory_<run_id>.jsonl`) is the input to `/scrutinize trajectory:<run_id>` audits (Agent-as-a-Judge, DevAI benchmark) and a verbatim audit record: emit through the helper only, never edit it. All emission is skipped under `--no-trajectory`. The invariants, enforced by the phases below and self-checked by `--verify`: - **Pairing.** Every `step_start` has a matching `step_end` (same step number); step 0 (plan-load) is paired too. Every `wave_start` has a `wave_end`. - **Sequencing (sequential waves / no-wave runs).** Emit each `step_end` before the next `step_start`; never open step N+1 while step N is open. **The helper enforces this at emit time (v1.7):** a `step_start` opened while a step is still open (outside ...