Improve release and rollback playbooks for team workflows

Background

Release, rollback, and hotfix practices are central to team Git workflows. The current content covers the basics, and the next step is to make the operational path clearer.

Scope

Review and improve:

• 04-github-engineering/release-management.md
• 08-templates/hotfix-process.md
• 08-templates/release-note-template.md
• 03-team-collaboration/team-git-workflow-guide.md

Suggested additions:

• Release branch decision table
• Hotfix checklist
• Rollback plan examples
• Back-merge expectations
• Release note traceability to commits, tags, and PRs

Done When

• A team can follow the guide during a release or hotfix.
• Risky operations include clear checks.
• Templates remain easy to copy.
• python3 scripts/check-docs.py passes.