engine-develop-enginelisted

<!-- GENERATED by .engine/tools/codex_gen.py from .claude/skills/engine-develop-engine/SKILL.md — edit that source and regenerate; never edit this file by hand. --> ## Steps 1. This route is for developing the Engine itself. Choose the lane by **which repository holds the files the change edits**, and say which one you chose: - **This checkout is the Engine's own home** (its git origin is the recorded `home_repository`): enter and follow `.engine/operations/engine-development.md` here. - **The edited files live in the Engine's home repository and this checkout is the mechanic that builds it**: do not decline. Enter `.engine/operations/owned-product-build.md`, cut the isolated product worktree, and ground in that product's `.engine/operations/engine-development.md` read at the worktree's resolved base commit — never its working tree — *before* planning, so the trust model and the invariants that govern planning are in hand first. - **The edited files live in this repository instead** (its own spec corpus, runbooks, and the like): say so and leave this route. That is an ordinary Build here, not Engine development. - **The change spans both repositories**: two Builds, one per repository, sequenced — never one worktree, and never a refusal. Take the Engine's home repository first through the mechanic lane above, then the work in this repository as its own ordinary Build. - **Anything else**: say plainly that this project consumes the Engine as released updates an