feat: add automated production release PR workflow

[offich]

Description

Added a GitHub Actions workflow that automatically creates a release PR from develop → release
whenever changes are pushed to the develop branch. The PR body is generated using the git-pr-release gem with an ERB template.

What was done

• Added .github/workflows/create-release-pr.yml
  • Automatically creates a release PR targeting the release branch via git-pr-release on every push to develop
  • Uses actions/checkout@v6.0.2 and ruby/setup-ruby@v1.299.0 pinned to commit hashes
• Added .github/templates/git-pr-release.erb
  • Release PR body template that automatically lists all included PRs

What was NOT done

• Creating the release branch (required separately)
• Configuring auto-merge for the release PR

Operation Confirmation

Setup & Steps

1. Ensure the release branch exists
2. Push to the develop branch — the workflow will trigger and automatically create a release PR from develop → release

Notes / Related URLs

• git-pr-release