Follow the Future Default adoption documents listed in the prompt. If the
installed and target Next.js versions differ, complete the version guide first.

## Adopt and verify

- [ ] Set `experimental.agentUpgrade` to the policy specified in the
      prompt, preserving unrelated configuration. If the installed Next.js
      version does not support this option, skip the setting and report why.
- [ ] Read and follow each adoption document in the prompt, in order. If none
      are listed, continue to delivery. Complete each adoption; remove temporary
      opt-outs and TODO markers after repair.
- [ ] Run the repository's checks, build when supported, and test affected
      runtime behavior. Verify each adoption before moving to the next.
- [ ] Complete the verification checklist in `shared.md` for each adoption
      before moving to the next.

## Deliver

- [ ] After verifying the adoption, return to `shared.md` and complete its
      delivery checklist.