Add .github/copilot-instructions.md and path-specific instruction files under .github/instructions/ to guide GitHub Copilot code review with project-specific conventions:

• Copyright attribution rules (VyOS Networks for new files, preserve originals)
• Changelog fragment key selection (trivial vs minor_changes vs bugfixes)
• Commit and PR standards (Phorge task IDs, test count accuracy)
• Test mocking patterns for resource modules vs legacy modules
• load_fixtures / filename parameter pattern
• Required test state coverage for resource modules
• Module option description conventions
• meta/runtime.yml redirect validation