git:20260903.96bdf96 to git:20260928.0562610

2 added, 0 removed. Audit A to A.

# Official plugins

- Keep `official-modes/index.ts` as the single plugin entrypoint.

- Keep each model's prompt and tool list in its own file under `official-modes/modes/`.

- Keep `@amp-agent-mode` directives and literal `createAgent` model and effort values in the entrypoint so server metadata parsing works.

+ - Keep each official skill in `skills/<name>/` with its `SKILL.md` and reference files; the directory name must equal the frontmatter `name`. Do not put plugin code under `skills/`; Amp never loads it as a plugin.

+ - Do not add a skill whose name collides with a builtin skill in the Amp CLI (`core/src/skills/builtin/` in ampcode/amp); the builtin would mask it.

- Run format checks before committing.

- Treat GitHub `main` as the source of truth. The mirror workflow must only fast-forward Pierre.