docs: deduplicate on-pull-request-runner README → point to GitBook (DEV-4518)

[dvaliant]

Summary

• Replaces the full reference documentation in on-pull-request-runner/README.md with a short pointer to the canonical GitBook page
• Keeps: quick start YAML (audit mode), link to examples/consumer-workflow.yml, maintainers section
• Removes: full inputs table, how-it-works walkthrough, blocking/fork/features details — all now live at https://docs.gomboc.ai/integrations/continuous-integration-ci-build-systems/github-actions

Why

DEV-4518: the public docs page for GitHub Actions was updated to include the ORL Runner documentation. Keeping a full copy in the README would create drift as the action evolves. Single source of truth = GitBook.

What stays in the README

• One-paragraph description
• Link to full GitBook docs
• Minimal audit-mode quick start (enough to unblock a new user)
• Link to examples/consumer-workflow.yml for remediate mode
• Maintainers section (internal, not in public docs)

[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

Results:
0 new issues

View in Codacy

_{NEW Get contextual insights on your PRs based on Codacy's metrics, along with PR and Jira context, without leaving GitHub. Enable AI reviewer
TIP This summary will be updated as you push new changes.}