feat: publish npm package to GitHub Packages

[Copilot]

Switches the publish target from npmjs.org to GitHub Packages so the package appears in the repo's Packages section. No external registry secret is needed — authentication uses the built-in GITHUB_TOKEN.

package.json

• Package scoped to @marcomg-byte/offser (required by GitHub Packages)
• publishConfig.registry set to https://npm.pkg.github.com

.github/workflows/publish.yml

• Both jobs: registry-url → https://npm.pkg.github.com/, added scope: '@marcomg-byte'
• publish job: added packages: write permission, swapped secrets.NODE_AUTH_TOKEN for secrets.GITHUB_TOKEN
• npm view version checks updated to @marcomg-byte/offser --registry https://npm.pkg.github.com

README.md

• Install commands updated to npm install -g @marcomg-byte/offser
• Registry link points to GitHub Packages
• Workflow description updated to reflect GITHUB_TOKEN auth

[marcomg-byte]

@copilot This will make the following section be enabled?

[Copilot]

@copilot This will make the following section be enabled?

<img width="1436" height="659" alt="Screenshot 2026-04-10 at 1 00 32 p m" src="https://github.com/user-attachments/assets/54507d9e-9f62-4...

Yes! Once this PR is merged and a version tag (e.g. v1.1.5) is pushed — which happens automatically when a PR with a patch/minor/major label is merged into main — the publish workflow will run and publish @marcomg-byte/offser to GitHub Packages. After that, the "Packages" section will show the package instead of "No packages published".