Add YAML metadata blocks to GitHub agent files

[Copilot]

GitHub agent markdown files require YAML front matter with name and description fields to be recognized by the platform.

Changes

Added YAML metadata blocks to all three agent configuration files:

• .github/agents/documentation-writer.md
• .github/agents/project-maintainer.md
• .github/agents/software-quality-enforcer.md

Each file now includes:

---
name: Agent Name
description: Brief description of agent responsibilities
---

This enables proper discovery and display of the agents in GitHub's interface.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>[Feature]: Missing yaml metadata blocks on GitHub agent files</issue_title>
<issue_description>### 🎯 Problem Statement

The new GitHub Agents markdown files don't show up in GitHub

💡 Proposed Solution

GitHub Agent Markdown files must have a YAML metadata block containing "name" and "description" values.

🔄 Alternatives Considered

No response

📝 Additional Context

No response

🤝 Contribution

• I would be willing to implement this feature</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [Feature]: Missing yaml metadata blocks on GitHub agent files #32

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💡 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.