Complete the distribution metadata and publish flow for the unscoped
`gitea-axi` package:
- add `repository`, `homepage`, and `bugs` to package.json
- add `publishConfig` (public access, npmjs registry) so `npm publish`
needs no extra flags
- replace `prepublishOnly` with `prepack: npm run build`, so both
`npm pack` and `npm publish` rebuild `dist/` first
- document the single-command flow in PUBLISHING.md
- add a packaging smoke-test tier (`test:pack`) that packs the real
tarball, installs it globally, and drives the installed binary
(`--help`, dashboard header, and `setup` finding the bundled skill)
