Adds workflow to only deploy docs

[milanholemans]

The idea is to create a workflow that only deploys the docs without creating a new release on npm.
This allows us to be more flexible when merging docs PRs.

[Copilot]

Pull request overview

This PR adds a new GitHub Actions workflow to deploy documentation to GitHub Pages independently of the npm release process. The workflow enables more flexible documentation updates by decoupling docs deployment from package releases.

Key Changes:

• Introduces a manually-triggered workflow for deploying documentation
• Reuses the established docs build and deployment pattern from the release_next workflow
• Properly scopes permissions for GitHub Pages deployment