Add branch protection configuration for main branch

[Copilot]

Main branch lacks protection against force pushes, deletion, and merging without review or status checks.

Configuration Files

.github/settings.yml - Branch protection rules for Probot Settings app or manual application:

• Prevents force pushes and deletion
• Requires 1 approving review before merge
• Requires build status check to pass
• Dismisses stale reviews on new commits
• Requires conversation resolution

.github/workflows/branch-protection-check.yml - CI workflow providing required build status check:

• Linting (flake8 for syntax errors)
• Test execution
• Explicit contents: read permissions (CodeQL verified)

.github/CODEOWNERS - Auto-assigns reviewers on PRs

Templates

• Pull request template with type/checklist
• Issue templates (bug report, feature request)

Documentation

BRANCH_PROTECTION.md - Implementation guide covering:

• Three application methods (Probot app, GitHub UI, API/CLI)
• Working with protected branches
• Troubleshooting

Updated README.md Contributing section with branch protection reference.

Application

Configuration files are repository-ready but require manual activation:

1. Install Probot Settings (auto-applies .github/settings.yml), or
2. Apply rules via GitHub Settings → Branches → Add rule, or
3. Use GitHub API/CLI (examples in documentation)

Original prompt

address this: Your main branch isn't protected
Protect this branch from force pushing or deletion, or require status checks before merging. View documentation.

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.