AI-ize the repo with instructions and skills

[goodtocode]

Setup the repo to be AI centric with the proper copilot instructions, coding standards, library references, skills and tools.

.github/
  copilot-instructions.md
  instructions/
    src.instructions.md
    tests.instructions.md
    docs.instructions.md
  skills/
    coding-standards.md
    clean-architecture.md
    blazor-fluentui.md
    goodtocode-domain.md
    goodtocode-validation.md
    goodtocode-mediator.md
    patterns-port-adapter.md
    patterns-inbox-outbox.md
  tools/
    domain.yml
    validation.yml
    mediator.yml
AGENTS.md