Add GitHub Actions workflow for deploying GitHub Pages preview

[dshevtsov]

Purpose of this pull request

This pull request (PR) adds a GitHub Actions workflow for deploying GitHub Pages previews and cleans up the .gitignore file.

Changes include:

• New workflow: Added deploy-github-pages.yml that enables manual deployment of GitHub Pages previews via workflow_dispatch. The workflow:

  • Accepts a branch input parameter (defaults to main)
  • Uses the reusable workflow from AdobeDocs/commerce-contributor
  • Configures appropriate permissions for GitHub Pages deployment

• Gitignore cleanup:

  • Added .cursor directory to ignore list
  • Removed obsolete entries (gatsby-specific ignores, unnecessary negation patterns)

Affected pages

N/A — This PR modifies CI/CD configuration and repository settings only. No documentation content is affected.

Links to the public Commerce codebase

N/A