Update copilot instructions with best practices from mvstrategies

WHY: Copilot instructions needed modernization with proven patterns
WHAT: Applied priority-based structure, decision trees, and collaboration principles
HOW:
- Added [P0/P1/P2/P3] priority sections for better navigation
- Implemented 3 core collaboration principles (test-first, sequential, task order)
- Added decision trees for common problems (test failures, new universes)
- Enhanced with code patterns and session checklists
- Removed irrelevant content (FTP, PHP, database, WebAuthn)
- Updated typer version reference to 0.12.3
- Streamlined future enhancements roadmap
- Added metadata footer with document versioning

TESTED: Reviewed against mvstrategies/.github/copilot-instructions.md v2.0

Author: lieblm