Copies a local jar under pack/custom/ (served by caddy), sha256s it, writes pack/mods/<slug>.pw.toml per packwiz "Other external files", then packwiz refresh. Cautious: halts on bad side, whitespace in filename, or existing entry without --force. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>