Adopt NuxtStart changes

Maintain an adoption map: every upstream-changed path belongs to one bounded area with a recorded integration decision.

1. Establish the baseline

1. Read the repository instructions and inspect the current branch, worktree, history, and remotes.
2. Confirm the lowercase nuxtstart remote exists with git remote get-url nuxtstart. When it is absent, offer to add it and ask the user for permission (Repo: nuxtstart/nuxtstart).
3. Begin integration from a clean worktree. When local changes exist, show the exact paths and ask the user to commit, stash, or authorize a safe preparation step.
4. Record the pre-pull HEAD, then fetch with git fetch nuxtstart --prune.
5. Resolve the upstream default branch with git symbolic-ref --quiet --short refs/remotes/nuxtstart/HEAD. If that ref is absent, obtain the remote's advertised HEAD instead of guessing a branch name. Record both the remote-tracking ref and its branch name, such as nuxtstart/main and main.
6. Find the merge base with git merge-base HEAD <upstream-ref>. If none exists, report that an adoption baseline cannot be established and ask for one.

This step is complete when the child HEAD, upstream ref and SHA, merge base, and clean-worktree state are known.

2. Build the adoption map

Start with compact manifests rather than opening every historical commit: