implement-speclisted

# Implement spec The implementation loop. Everything that makes it unattended lives in the preconditions and the gates — the coding itself is the ordinary part. ## Preconditions Check all four before the first edit. A missing one is a stop condition, because starting without it guarantees the interruption you are trying to avoid: 1. **The spec** exists at `docs/specs/<id>.md` with steps that carry verify commands. Thin spec → run `spec-forge` first. 2. **The map** at `docs/agent/repo-map.md` is current, so the workspace kind, the stack per project, the gate commands and the changed-set command are known. Missing or stale → `repo-cartograph`. 3. **The contract** is confirmed for every endpoint the spec touches — `api-contract-sync`. Implementing against an assumed shape wastes the whole run. 4. **The ledger** exists at `docs/specs/<id>.assumptions.md`, even if empty. Read `agentic-guardrails` before starting. It carries the ledger format, the repair budget, and the shortcut list. Branch from the base branch named in the map. Work on a branch, always — an unattended run needs somewhere to roll back to. **Commit anything the preconditions produced before branching.** A freshly written repo map, a `CLAUDE.md`, an installed hook set — these belong to the repo, not to this ticket. Left uncommitted, they land in the feature branch and put the changed set permanently outside the blast radius, so the check at handover reports a mismatch that is real but says nothing about the f