copilot-instruction-layering

# Skill: Copilot instruction layering ## Goal Provide a small set of reusable Copilot instruction files that can be copied into new repos and applied conditionally based on project type. ## Files - `.github/copilot-instructions.md` (high-level, Makefile-first) - `.github/instructions/*.instructions.md` (stack-specific guidance) ## Conventions - Keep instructions short and actionable. - Prefer conditional language ("Applies when...") so these files can coexist in mixed repos.