- upgrade.sh: automates backporting upstream Go net package changes
- Downloads Go source tarballs for CUR and UPSTREAM versions
- Copies unmodified files directly from upstream
- Performs 3-way merge (diff3) for TinyGo-modified files
- Detects per-file CUR version from TINYGO headers
- Generates detailed diff reports in .upgrade-report/
- Supports --dry-run mode for previewing changes
- .gitignore: add .upgrade-work/ and .upgrade-report/ directories