Added initial GH Copilot instructions

[Micky774]

Description

Includes an initial addition of repository-level AI agent instructions/context via CLAUDE.md as well as an example skill via .claude/ck-debugging/SKILL.md. This mainly serves as a demonstration of how to add additional context to AI coding agents, as well as how to develop a reasonably-complex skill.

TODO: Back-test against old cases and refine as needed

Type of change

• Documentation change (change only to the documentation, either a fix or a new content)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Infra/Build change
• Code refactoring

Changes

Please list the changes introduced in this PR:

• Adds CLAUDE.md
• Adds .claude/ck-debugging/SKILL.md

Checklist:

• I have read and followed the contributing guidelines
• The functionality is complete
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes