pnpm lockfileVersion downgrade path after major upgrade
Context pnpm's pnpm-lock.yaml carries a lockfileVersion field that changes across major releases. When a team upgrades pnpm (for example from v8 to v9), the lockfile is migrated to the new schema. The older pnpm version cannot parse the upgraded lockfile, so a rollback requires either restoring the previous lockfile from version control or regenerating it wi