Copilot instruction layering

通过可复用的条件性指令文件，实现指令分层。

SKILL.md

--- frontmatter

name: Copilot instruction layering
description: instruction layering with reusable, conditional instruction files

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, with applyTo globs)
•.github/skills/*/SKILL.md (reusable skill definitions)

Conventions

•Keep instructions short and actionable.
•Prefer conditional language ("Applies when...") so files can coexist in mixed repos.
•Use applyTo front matter to scope instructions to relevant file patterns.