Next Upgrade

Handles Next.js upgrades by reading your current version from package.json, fetching the official migration guides, and walking through the proper upgrade sequence. It runs the appropriate codemods first to automate breaking changes, then updates dependencies in the right order, and points out manual migration steps you'll need to handle. The incremental approach is smart since jumping multiple major versions at once usually breaks things. It catches the common gotchas like async params in v15 and configuration changes that trip people up, then verifies everything builds correctly before calling it done.