reconcilelisted

Eliminate architectural drift by reading passing spike/feature code and reverse-updating the HLD/LLD doc to match reality. $ARGUMENTS is the path to the HLD or LLD file (e.g. `design/lld-user-auth-service.md`). The path may be omitted if it's already clear from this conversation — see step 1. Steps: 1. Determine the target path: - If $ARGUMENTS contains a path, use it. - If not, look back through this conversation for an HLD or LLD path already established (created via `/hld`/`/lld`, or referenced by an earlier `/spike`, `/add-spike`, `/resolve-open-questions`, `/implement-lld`, or `/reconcile` call in this session). If exactly one is found, confirm it with the user before proceeding rather than silently assuming. If more than one is found, list them and ask which to use. If none is found, ask the user to provide a path and stop. - Check that the file at that path exists. If it does not, tell the user and stop. 1. Read the file's frontmatter for `**Last Reconciled:**`. Determine scope: - If a sha is present, diff `git diff <sha>` (not `<sha>..HEAD` — a plain single-ref diff also picks up uncommitted working-tree changes, which a commit-to-commit range would silently miss if nothing's been committed since the last reconcile). - If blank, find the actual base to diff against — not necessarily the default branch: - Detect the current branch: `git branch --show-current`. - Detect the repo's default branch: `git remote show origin 2>/dev/null | grep 'H