[AI] Ship bundled docs in next and generate AGENTS.md in create-next-app (#89850)
AI coding agents often rely on outdated training data when working with
Next.js projects, leading to hallucinated APIs and deprecated patterns.
This PR addresses that by shipping version-matched documentation inside
the `next` npm package and generating agent instruction files during
`create-next-app`.
During `next` build, a new `copy_docs` task copies `docs/` from the repo
root into `dist/docs/`. Since `"dist"` is already in the package's
`files` array, the docs are automatically published at
`node_modules/next/dist/docs/`.
`create-next-app` gains a new `--agents-md` / `--no-agents-md` flag
(defaults to `true`). When enabled it writes two files:
- `AGENTS.md` — instructs agents to read `node_modules/next/dist/docs/`
instead of relying on training data
- `CLAUDE.md` — uses `@AGENTS.md` import syntax for Claude Code
The option appears in the recommended defaults display and is prompted
during the customize flow. Existing tests are updated with
`--no-agents-md` to avoid the new prompt.